Terroir effect on aromas in grapes and wines

 

Dr. Cornelius van Leeuwen has constructed an extensive overview on the topic of how 'terroir' impacts grape and wine aroma on a molecular basis and how those aromas are influenced by climate and soil. In other words, this article adds to the investigation and discussion on how place affects product..in this case, wine. 

What is not objective or scientific about that? 

Check it out ...you may even take the time to actually read it, if you dare! 

Recent advancements in understanding the terroir effect on aromas in grapes and wines

FIGURE 2. OVERVIEW OF THE TERROIR EFFECT ON AROMAS IN GRAPES AND WINES. 

Terroir expression is mainly mediated through (1) air temperature (climate), (2) radiation (climate), (3) vine nitrogen status (4) and vine water status which results from (A) soil water holding capacity (soil), (B) reference evapotranspiration (climate) and (C) rainfall (climate). These four components related to soil and climate impact aroma composition and expression in grapes and wines. By connecting recent advances in the understanding of the impact of environmental factors on aroma expression, wine typicity in relation to terroir can be better understood.

Two 'new' wine grape hybrids

'Dazzle', new grape from a cross made in 1991 between Gewurztraminer and a NY hybrid, Melody by the late Dr. Jim Moore, and released by Dr. John Clark, University of Arkansas. 

'Indulgence', another new wine grape from the University of Arkansas grape breeding program. It has muscat character in the fruit, and is the result of a 1988 cross between Muscat Ottonel and popular hybrid, Seyval.

Click on the link below to read about the new varieties: DAZZLE and INDULGENCE

New Grape Varieties from Arkansas

Got Excise Tax?

Just in case you missed the email notice below from Mr. Christopher Goblet executive director of NM WINE... STOP CRAFT BEVERAGE EXCISE TAX INCREASES National Day of Action - Dec 1st, 2020 Our federal advocacy group, Wine America, has been busy working members of Congress to ensure the Craft Beverage Modernization & Tax Relief Act (CMBTRA) stays in place. They are once again asking the wine industry to take a moment to urge Congress to extend the CMBTRA. They have set up a website that allows you to input your address and zip code, and an automatic email will be sent to your House Member and both of your Senators. The website for the LAST CALL DAY OF ACTION is here: STOP CRAFT BEVERAGE EXCISE TAX INCREASES. Please do not use it until December 1st. You are also encouraged to share this link with your wine club or on social media. Here are some scripts that you can cut and paste if you want to help push this agenda December 1st. TEMPLATE EMAIL: Last year, Congress passed a one-year extension of the Craft Beverage Modernization and Tax Reform Act (CBMTRA) that will soon expire. CBMTRA is important to our business as it extends a federal excise tax reduction for craft beverage alcohol producers like us.  This allows us to make critical investments back into our business like:  Buying more grapes and fruit from farmers  Purchasing more equipment from manufacturers  Providing new job opportunities  Giving back to our community  Continuing to make great products for consumers like you to responsibly enjoy!  However, this one-year extension expires on December 31st, 2020. If Congress doesn’t act before then, craft beverage alcohol producers across the nation will face tax increases. We are already hurting economically due to COVID-19, and a tax increase would be devastating to many businesses like ours.  We need your help in urging Congress to #StopCraftTaxIncreases this year! How can you help? TAKE ACTION HERE and tell your Members of Congress how CBMTRA will impact our winery.  SOCIAL MEDIA POST: LAST CALL! We need YOUR help to urge Congress to #StopCraftTaxIncreases. If Congress doesn't pass CBMTRA BEFORE the end of the year then craft beverage alcohol producers will face a devastating tax increase. TAKE ACTION HERE: https://p2a.co/cbZswMu

Experimental Design for Mulch Study

    Take a minute to study the layout depicted in the cartoon schematic of the vineyard at Los Lunas ASC. The mulch treatments are: wood chip mulch, pecan shells and herbicide treated soil strip (bare). All treatments are located under the trellis and are ~ 3 ft. wide. The effects of the designated plots and will be evaluated over the next 3 years. Some dependent variables we will investigate, measure and evaluate are: soil moisture, soil temperature, vine performance (dormant pruning weights, vine phenology or seasonal development, yields and berry composition at harvest: titratable acidity, soluble solids, pH and YAN: yeast assimilable nitrogen). The two main cultivars to be established into the different mulch plots are Touriga Nacional, a traditional port variety, and Refosco, a red grape typically grown in Northern Italy. I welcome your comments.

What does a soil test mean? and a recommendation

 

    I have had a call out for many months for any New Mexico grape grower to send me a soil sample and I will submit it to a lab and have it analyzed. I then receive the results and help the grower interpret the results and make any additions or amendments to his or her vineyard soil. I recently had one client who said "thank you, and I will go on the internet and see what it means".  I can only wish that grower "good luck" Not to say that the internet doesn't have some solid information, I just don't know how applicable it is to specific New Mexico soils, growing conditions and our unique environment, of which there are many. Keep in mind that New Mexico has as many as 10 different growing zone designations. The only other US state with that many growing zone designations is California. 

Having said that, if you do go to the internet ...to: "see what it means", a good starting place is: Vineyard Nutrient Management in Washington State

The publication was authored by Washington State's Dr. Michelle Moyer in 2018, and much of what Dr. Moyer has composed and included applies here in New Mexico.

Laying Down Mulch...under-trellis

    The crew at the NMSU Los Lunas Agriculture Science Center ( NMSU LL ASC )  helped install the latest applied viticulture study in the experimental vineyard there. Dr. Marisa Thompson, NMSU Urban Horticulture Extension Specialist and I have designed and will follow and document the differences in vine performance and soil health due to mulch compared to herbicide treated strip as a control under-trellis.  The mulch treatments we will evaluate are: commercially available wood-chip mulch and pecan shells, donated by Stahmann's Pecans Inc., Las Cruces NM. The two cultivars are: Touriga Nacional, a traditional port wine cultivar and Refosco, an Italian red  that has performed well in southern New Mexico in the Mesilla Valley AVA and at the Farmington ASC, located on NAPI (Navajo Agricultural Products Industry, Farmington, NM, NAPI ) lands in the four corners region of New Mexico. Notice that I used the descriptor, "under-trellis" instead of a more common term, "under-vine". I think this distinction is important as "under-vine" may infer to some that the treatment is subterranean in nature and physically below the vines. This is obviously not the case, but the mulch placement is more accurately described as being located under the trellis. Take a look at the photos below and decide for yourself. 

Loading the 'gator' to transport wood-chip mulch down the plot rows

Tom Place, Los Lunas ASC Superintendent, brings front-loader bucket of mulch to
be off-loaded by Carl (front center) and Chuck (right).

A typical plot before application of wood-chip mulch

A typical plot after application of the wood-chip mulch laid down
the vine row in a ~3 ft. wide strip about 4 inches deep under the trellis. 

This is crown gall; abnormal gall growth on a grapevine at the graft union. Crown gall is a disease that causes the plant to produce these initially fleshy tumors. The environmental insult that typically induces this disease to present itself is low winter temperatures. The primary crown gall disease of grape is caused the bacterium Agrobaterium vitis. Will the mulch treatments mitigate the occurrence of this disease if it is 'hilled up' over the graft to "protect" it over the winter?

Bud Mortality Counts at Los Lunas vineyard

The table below contains results of bud dissection and assessment of approximately 276 dormant buds. Each bud's primary, secondary and tertiary growing points were inspected and if they appeared black instead of healthy green in color they were marked as "dead". Upon first glance it appears as though the one year old Touriga Nacional vines fared the worst with about 86% of its primary growing points appearing dead, followed by Petit Verdot. I will repeat this assessment later in the year when we begin dormant pruning and use the mortality then to determine how many buds to leave for the 2021 growing season. 

Buds Reveal Cold Damage ...

    The photos below were collected Thursday, November 12, 2020. Dissecting the dormant compound buds on grapevine canes can reveal damage to the growing points. At the Los Lunas ASC vineyard, the temperatures dipped into the teens in late October...just days before Halloween when it snowed about 6 inches. All vines were in the green vegetative state and were just beginning to "shut down" and begin the acclimation process. When a grower mentioned to me that he was going to cut some buds and inspect them for possible damage I decided to do the same. Most of the buds I cut and inspected were viable and in good shape...some however, were not. Look for yourself at dissected buds visible in the photos below.  

First, I  selected several sections of dormant canes and brought them inside. They were held for ~24 hours at room temperature and provided with water to keep them hydrated. 

The first bud I dissected by cutting the top 1/3 of the bud off, revealed that both the primary and secondary growing points were black and likely non-viable. The third bud or tertiary bud, seen here on the right of the section is green and is likely viable. The tertiary buds can grow new vegetative tissue but is usually non-fruitful.  You can do this at home ....simply use a very sharp knife or better yet a razor blade to cut off the top 1/3 of the bud in question. A hands lens is useful to magnify the dissected bud for more clarity,  especially if your eyes are like mine. 

All three buds or growing points appear green and viable in this bud. Well, they were until I cut the bud open to inspect it! But with only one short section of cane harvested from each vine...minimal to no damage is done, relative to the pruning that will occur later this winter. This bud was taken from the relatively new hybrid variety: Enchantment. Enchantment is a recent release from the University of Arkansas, and is a teinturier variety, meaning its berries have red flesh as well as red skin. 

Notice the cinctured area on this cane. It was caused by its own tendril wrapping around the cane as it grew. The tendril is seen here removed, and lying to the right of the cane. Not sure if this constriction hindered the growth of the cane...but it is something to be aware of and if seen, cut away to allow the cane to grow 'normally'. 

Pruning Philosophy

Introduction: Pruning is arguably the most important cultural practice a grape grower does. Grapevines are pruned to regulate the amount of fruit they produce each year. Without pruning, yes the vines would produce fruit, and that fruit can successfully help the plant continue its genetic journey. But such fruit rarely achieves the amount and quality to support a consistent economic return to a grower.  
    Pruning has an overall dwarfing or depressing effect on the vine. that is, pruned vines are made physically smaller while the vigor of remaining growing points is increased. When wood or top growth is removed, the roots that previously supported the above ground growth will have an abundance of hormones and carbohydrate reserves and a greater water and mineral absorbance capacity relative to the remaining top growth. This excessive supply of water and minerals stimulates the remaining shoots to grow expand at a rapid rate. The rate of growth over time is referred to as "vigor". Vigor should not be confused with the total amount of growth or overall vine size. To summarize: pruned vines are physically smaller than unpruned vines and remaining shoots are more vigorous compared to shoots on unpruned vines.
    The descriptor "vine capacity" is often confused with vigor. Vine capacity relates to vine size, and is a separate concept. Capacity is the total amount of fruit or crop a given vine can support to a desired degree of maturity. Vine productivity and sustainability depends on vine capacity. First, capacity dictates the vines's physiological requirements and secondly it impacts the economic viability of the vineyard as enterprise. When you prune, you determine:
        1. type and position of fruitful buds
        2. bud number: which impacts crop load, berry composition: % sugar, acid content, pH, flavor, aroma and color compounds that determine fruit 'quality'   

Purpose of pruning: to achieve the desired amount and quality of fruit over a number of years.
        1. Set the appropriate fruit load to the vine's size and capacity, accomplished by leaving an appropriate number of buds on the vine at pruning.
        2. Shape and training the vine to a given trellis system. Vine growth is directed into a well-spaced canopy to allow air, sunlight and spray materials into the canopy. The goal is to ensure the optimum amount of sunlight strikes foliage and fruit at the optimum time over the course of the day and growing season. A successful grape grower is simultaneously mindful of the current and subsequent seasons when considering pruning and training tasks.  

Balanced pruning: How many buds to leave?
    Weigh all one-year old wood that is pruned off the vine. Count the remaining buds. Leave 30 buds for the first lb. of wood removed and another 10 buds for every lb. over the first pound. This, ‘30+10’ formula was developed for American varieties of Vitis labrusca, such as Concord, Himrod, Glenora, Niagara, Suffolk Red, etc. For Vitis vinifera or European wine grape cultivars: Chardonnay, Cabernet Sauvignon etc., begin with 20 buds per 1 lb. of wood removed or a 20 + 20 system. These ‘formulas’ are intended as a starting place and are not definitive. They help match bud numbers and subsequent leaf area to the crop it must support. Balanced pruning uses:
        1. cane weight, only one-year wood is weighed
        2. bud or nodes counted and left on the vine 
        3. begins with a pruning formula for estimating vine capacity to match buds to leaf area
    Dr. Nelson Shaulis, of Cornell University, utilized this technique in the middle of the 20th century to help grape growers determine the number of nodes or “buds” to retain at pruning. The process assumes the selection of well-exposed canes with fruitful buds. Pruning formulas are driven by growth and fruiting characteristics of the variety and their environment. Vine capacity varies between trellis/training systems and between adjoining vines in a row. The goal is to avoid over or under-pruning vines of differing capacities. Balanced pruning is a first step in achieving the annual desired quality level while maintaining or improving vine capacity for the following years’ crops (Coombe and Dry, 1992). 

Example bud number formulas:

Variety Formula                    Variety                     Formula                                                 

Cabernet Sauvignon 20+20 Concord                   30+10

Cabernet Franc         20+20 Niagara                    40+10

Chardonnay         20+20 Vidal (hybrid)          15+10

Riesling                 20+20 Seyval (hybrid)          5+10

Other hybrids            20+10

A measure of vine capacity: leaf area : fruit ratio 
    The leaf area to fruit ratio is defined as: Pn (photosynthetically active) leaf area measured in square centimeters (cm2) to mass of fruit measured in grams (g). This ratio depends on the trellis system used. The vertical shoot positioned (VSP) trellis generates a leaf area : fruit ratio of about 0.8 to 1.2 m2 leaf area per kg fruit or about 10 cm2 of leaf area per 2 g of fruit, about 5-6 mature leaves per each medium sized cluster. Divided canopies can be a bit more efficient, where only 0.5 to 0.8 m2/kg are needed to mature fruit (Figure 1). 

Figure 1. Above left:The relationship of leaf area to crop weight. Below right: Examples of three trellis systems: A1 = vertical, B1 = lyre and C1 = Geneva double curtain, (Kliewer and Dokoozlian, 2005). 

1. Example: Assume the European winegrape, V. vinifera, vine you have pruned produced 3.5 lb. of pruning wood. Applying the 20+20 formula would result in 20 nodes left for the first pound of canes, plus an additional 20 nodes for each pound above the first. Thus, the 3.5 pound of wood would indicate to leave 70 buds or nodes on the vine. However, in practice, if the vines occupy 6 ft of trellis, and it is recommended to leave 6 buds/ft., or 2-3 spurs per foot, this would result in ~ 42 buds on the vine not the 70 indicated by the formula. The bud number per foot of cordon/trellis is more important than the total number of buds per vine because to leave more would result in a very dense, shaded canopy. Remember, a vine canopy with well-spaced shoots, leaves, and clusters is desired. Prune to avoid a crowded, dense canopy that increases disease and insect pressure, and has poor light exposure of leaves and fruit clusters. 

2. Wood : fruit ratio should be approximately 5-6 or 5-6 lb. of fruit per 1 lb. of wood removed. In other words, a vine that produces 2 lb. of pruned one-year old wood is likely capable of supporting 10 to 12 lb. of fruit the following season.

Factors that impact pruning…or, pruning depends on:
    Climate: Is your climate continental or maritime? New Mexico has a continental climate with a high likelihood of winter and/or frost injury due to wide swings between night and day temperatures (diurnal range). There is little to no dampening effect from humidity or large bodies of water. In this case:
        1. Leave more buds at pruning time and be prepared to shoot/crop thin later in the season.
        2. Prune late, this will delay budburst and possibly avoid frost injury in the spring.
        3. Consider “kicker canes”. These are ‘extra’ canes left on the vine. Kicker canes can enter budburst relatively late and can replace buds killed by frost. If kicker canes are not used, they are typically replaced each year. Kicker canes can reduce or mitigate excessive vine vigor or be positioned and used as a replacement trunk. 
    Soil Fertility: 
        1. deep soil = vigorous growth, prune lightly (leave more buds) to decrease rate of early shoot growth
        2. poor soil = prune severely (leave fewer buds), to stimulate vigor in remaining buds
    Variety: dictates: bunches/shoot, flowers/cluster, berry weight, and bud position.
        1. Some varieties have basal buds that are seldom fruitful, example: Nebbiolo and Thompson Seedless.
        2. Other varieties have basal buds not counted at pruning time, that can burst and grow
            later leading to a congested canopy. 
        3. Apical dominance? This phenomenon is most evident in the spring. Buds at cane tips break bud first and subsequently, buds located below the 'top' (proximal to the base of cane) will break bud later. The grape grower can take advantage of this natural tendency by leaving longer spurs at the initial pruning pass. After the apical buds begin to grow, one then prunes them off. This removal of the apical growing buds will delay bud break in the remaining buds and their emergence later can help avoid damage due to late frost events.    
     Economic: Winter pruning is the most economical way to control crop, but it is not very precise. Cluster, fruit and shoot thinning during the growing season costs more, but is more precise, compared to winter or dormant pruning. 

Pruning Procedures 
1. Timing: Vines can be pruned anytime between leaf fall and bud break the following spring. Although early pruned vines can be more susceptible to winter injury. The earlier vines are pruned, the earlier they will break bud in the spring, and depending on timing, will be more likely to be damaged due to late frosts. When to begin pruning is dictated by size of vineyard and number of pruners available. Pruning should be completed by budburst. Experienced pruners can typically cane prune an acre of vines in 30 to 40 hours. Pruning after budburst increases risk of bud damage, because the tender buds can be damaged or knocked off.  
Early pruning = early bud break, growth advancement can persist through harvest
Double pruning = Make two passes through the vineyard. 
--First pass: make rough cuts and remove the pruned wood from the trellis
--Second pass: adjust bud numbers to desired number/vine prior to bud break
Delayed pruning: pruning near budburst will delay development of remaining buds 
--The delay in growth can persist through harvest
--Delayed pruning until after apical shoots are well emerged and growing can reduce yields     somewhat. This can be used to advantage in reduction of the amount of required cluster         thinning later in the growing season.
--Vines ‘bleeding’ sap will not be injured by spring pruning…but young buds can be knocked off by pruning and wood removal. Therefore, all pruned or unwanted wood should be removed from the trellis before the bud swell. 
--Delayed pruning can reduce eutypa, esca, botryosphaeria and other wood rotting diseases (Figure 2).

Figure 2. Left: a cross section of a cordon infected with fungal wood rotting disease, evident in the discoloration. Right: end-cut cordon revealing fungal wood rotting infection. 

2.  Pruning Degree:
--Balanced pruning: buds retained are based on weight of wood removed at annual dormant pruning
SEVERE              < 20 buds left on the vine 
MODERATE             20 to 70 buds left on vine
LIGHT             > 75 buds left on the vine 
 
3.  Cane Selection Criteria:
--Varietal color: light brown V. vinifera varieties, with brown coloration to the cane tip,
V. labrusca cultivars have a reddish-brown color
--1 cm (3/8 inch) in diameter, strive for cane uniformity
-- moderate internode length, about 3-4 inches
-- canes of different length and diameter should retain different number of buds
-- age or location of canes and spurs is dependent on training and trellis system 
4. Vine Age: Use different training goals for different age vines. 
-- young vines – establishment of framework based on trunk arrangement
-- mature vines – framework and bud type placement within trellis system


    Pruning affects most vineyard activities and vine growth parameters such as: crop yield, winter hardiness, insect and disease management and ultimately, berry composition and the resultant berry, juice and wine quality (Chapman et al., 2004). With practice, pruning can become intuitive. A grape grower with an eye towards a long-lived vineyard should maintain good records to supplement and support her pruning decisions. 


REFERENCES
1. Chapman, D.M., Matthews, M.A., and J.X. Guinard. 2004. Sensory attributes of Cabernet
        Sauvignon wines made from vines with different crop yields. Am. J. Enol. Vitic. 55: 325-334.
2. Coombe, B.G., and P.R. Dry. 1992. in,Viticulture Volume 2, Practices. Winetitles. Adelaide, Australia
3. Kliewer, W. M. and N. Dokoozlian. 2005. Leaf area/crop weight ratios of grapevines: influence on
        fruit composition and wine quality. Am. J. Enol. Vitic. 56:170-181.
4. Skinkis, P.A. and A.Vance. 2013. Understanding Vine Balance, an important concept in vineyard
        management https://ir.library.oregonstate.edu/xmlui/bitstream/handle/1957/39883/EM%209068.pdf
5. Winkler, A.J., Cook, J.A., Kliewer, W.M., and L.A. Lider. 1974. in, General Viticulture. University of
        California Press, Berkeley.
6. Reynolds, A.G. and T.K. Wolf. 2008. Pruning and Training, 98 -123, in, Wine Grape Production
        Guide for Eastern North America. T.K. Wolf, ed. Natural Resource, Agriculture and Engineering
        Service (NRAES) Cooperative Extension, Ithaca, NY. 
7. General information on pruning and other grape growing techniques and tools:
        eViticulture http://eViticulture.org 

New Disease Resistant Winegrape Cultivars

 Disease Resistant Varieties from UC Davis

Whitehall Lane may look idyllic, but there's a war going on here against microscopic enemies of the grape. (Courtesy of Whitehall Lane) 

Dr. Greg Jones WEATHER FORECAST

Yes, New Mexico we are still in a drought.

Figure 2 – Western US year to date (January-October) temperature departure from normal (top) and percent of normal precipitation (bottom; images from WestWide Drought Tracker, Western Region Climate Center; University of Idaho).

Check out the full weather forecast and climate characterization for the upcoming winter season from Dr. Greg Jones of Linfield College in Oregon. Dr. Jones is a world-renowned climate expert..especially in relation to winegrowing. Check out his website and publications that go deep and broad into understanding the impact of weather/climate on grapevine growth and performance...and ultimately their  impact on wine. 

Dr. Gregory Jones, Weather Forecast  

Comments on cane color

    Cane color should be noted post-harvest as your grapevines lose their leaves and 'go dormant'. The proper color is indicative that they have hardened off or lignified after adequate exposure to sunlight during the growing season and have stored sufficient carbohydrates to survive the impending winter season intact. When pruning later in the winter or early next spring, these characteristic colors should be selected for in the canes and spurs you choose to leave as fruiting canes in the upcoming vintage. Another characteristic of note, is internode length. Most sources suggest a node spacing or internode length of about 3-5 inches...or about a 'fist width'. Check out the photos below. These were taken at the NMSU Los Lunas experimental vineyard on Friday, October 30th. 

Recently defoliated canes of Cynthiana/Norton (Vitis aestivalis x Vitis vinifera). Notice the dark red color of the periderm or bark of the canes. This red coloration is characteristic of this cultivar.

This is a cane with typical bright brown color of most Vitis vinifera cultivars, the European wine grape.

Back to 'normal' ?, and the cover crop to replace the buckwheat

 After record setting cold and an accompanying snowfall of about 6 inches on Monday into Tuesday October 27th, more seasonal temperatures returned Thursday and Friday. Here are some photographs of the transition.

The view of the Los Lunas experimental vineyard looking northwest, with dead foliage after the snow melted...and our iconic yucca in the background. If you look close you will see a small flock of Sandhill cranes making their way across the clear sky.

    Buckwheat that was planted back on September 9th, was killed by the cold weather this past Monday and Tuesday. But not to worry, we planted the next cover crop of wheat, rye, Daikon radish, turnip and Balanza clover on October 19th and it appears to have weathered the below freezing temperatures and is germinating through the dead buckwheat plants. 

Rows of dead buckwheat plants are visible in the interows.

Close inspection reveals the germinating seedling clover and "cole" crops; radish and turnip.

In addition to the clover and radish...rye and wheat are also visible....they appear as single spears at this point.

Record cold for October

     Deja vu all over again...Monday evening, October 26th thorough Wednesday morning October 28, recorded some cold temperatures. The city of Albuquerque set new records on Monday and Tuesday with a low of 19 degrees Fahrenheit over 5 hours. Monday's occurred late in the day and Tuesday's early in the day. Monday's record low broke the previous low for that day (25 degrees) by 6 degrees.  Tuesday's previous record low was 21, so the new record of 19 was only 2 degrees lower.

    In case anyone is wondering...yes, a similar unseasonably early cold snap hit the state last year at this time. And yes, it apparently did do some damage to area grapevines.  

    Look for a full report on these record temperatures and the regional climate as it impacts grape growing next month in November...after October 2020 is in the books.   

View of NMSU experimental vineyard Tuesday morning, October 27, 2020 with Cerro de Los Lunas west of I-25 and Los Lunas in the background.

Only in New Mexico is one likely to see a vineyard with a yucca plant in the background...covered in snow no less! Notice the Cynthiana/Norton (Vitis aestilvalis x Vitis vinifera ?) vine in the foreground was trying to acclimate to the cooler fall temperatures by evidence of its yellow leaves...when it was confronted with the sudden dip to 19 degrees Monday night and early Tuesday morning. The vines with entirely green foliage in the background, are various V. vinifera cultivars.

Second Cover Crop Germinating...and freezing?

The cover crop mix of Balanza clover, wheat, rye, turnip and daikon radish is beginning to germinate....but it is forecast to dip to about 19 degrees in Los Lunas on Tuesday morning. Will the young seedlings survive...we will see!

Existing rows of remnant buckwheat that is flowering. The second cover crop of wheat, rye, daikon radish, Balanza clover, and turnip was seeded with a no-till planter last Monday (October 19) and is just beginning to germinate.

Notice the small seedling clover (?) emerging in the seed row just below the buckwheat plants?

 

Mission Rose

 Mission (almost accomplished 😉) Rose Sensory Analysis Prior to Bottling

New Mexico's heritage variety: Mission.  Four rose wines: Daniel Goodrich (NMSU Viticulture Program Coordinator) and NMSU undergraduate, Fausto Barazinin-Rogel, received ~1,000 lbs. of Mission grapes from Teardrop Vineyards in Tularosa, NM courtesy of winegrower Barry Brown and Consultant Michael Dominguez. Michael was interested in New Mexico Mission as a heritage variety, and how rose wine made from them would turn out using two different yeasts: X-5 and DV-10.  NMSU viticulture partnered with Michael to produce four rose wines. The wines were fermented using each of the two yeast strains at two different temperature regimes, basically room or lab temperature and the other, much cooler at < 60 degrees F.  The winner as far as color and taste? The wine on the far left in this photo, X-5 yeast fermented at room temperature. Notice the 'Provence' style pink to salmon pink color? The wine has a full bouquet and aroma, a medium finish and many fruit and tropical notes throughout. All were finished completely dry. All wines have been cold and protein stabilized (with bentonite) will likely be blended together and then fined with Isinglass and filtered prior to bottling.  

Michael Dominguez assessing color of Mission Rose wines made at NMSU's Fermentation Lab, Fabian Garcia Agriculture Science Center, Las Cruces NM, October 21, 2020.

Second Seeding of Fall Cover Crop

 Cover crop seeding with no-till seeder

    The soil at Los Lunas vineyard still had some moisture in it today when we re-seeded a fall cover crop. 

The mix is a popular one used in eastern New Mexico. See the label with the mix components in photo below:

Cover crop seed mix with percentages of each component

Close-up of seed mix containing wheat, rye, Balanza clover, Daikon radish, and turnip

Here are a few photos of the buckwheat as it presented itself this morning...the seed germinated but never did thrive. It then began to flower without ever establishing the leaf architecture to support the blooms.

Buckwheat, about 40 days post seeding. Notice the white blooms

In the photos below Daniel Goodrich, NMSU Viticulture Program Coordinator, drives tractor with Great Plains no-till seeder. The Fall Cover Crop Mix shown above was seeded at about 100 lbs/acre.

Time for Terroir?

'Terroir': Is There Some Truth in Every Myth?

Abstract/overview: The word and concept of "terroir" has come to represent winegrowing traditions and beliefs, some of which date back 7,500 years to explain how grapevines grow, what wine contains and why it tastes the way it does.  Adherence to such beliefs (acceptance of something as true or real) and myths (widely held tradition, story, exaggerated or false belief) to explain winegrowing (the growing of grapes and finishing them to wine) prevents and/or hampers objective and open-minded investigation of grapevine physiology and wine sensory analysis (Matthews, 2015). Recently, "terroir" has been used as a marketing ploy (especially following the 1976 Paris wine tasting at which French judges determined that California wines were superior to French wines, in a blind side-by-side comparison). This essay provides a case study and peer-reviewed research into the effects of selected elements of "terroir": climate, soil , yield and vine spacing on grapevine performance. An application of sensory science, called 'descriptive analysis', used to explain how wine is perceived, is also presented.     

A working definition:
Terroir (“tair-wahr”): an ecosystem, in a given place, including many factors including: climatic conditions, cultivar and rootstock, geography and topography, soil characteristics such as mineral nutrition and water supply (Seguin, 1986)

    In contrast to the Seguin's definition, many who try to explain or apply 'terroir' often resort to complex, contradictory, subjective opinions, relying on tradition, unsubstantiated intuition and antidotal observation. Since the 1300's, winegrowing Cistercian monks in Burgundy, France have been credited with the concept of terroir as a 'sense of place' that imparts uniqueness and 'quality' to a wine form a specific region or vineyard (Patterson and Buechenstein, 2018). But is 'terroir' a 'sense of place' or a concept, a culture, a soil-based production system, a marketing ploy or all of the above? Whatever it is, many winegrowers, writers, critics, sommeliers, marketers and consumers 'believe in it' and embrace it (Morris, 2018). Thus 'terroir' seems the antithesis of empirical science and many viticulture scientists's view of it is summed up in quote from Dr. Marcus Keller or Washington State University: "... the concept of terroir is mostly meaningless, because something that explains everything (in one word!) ends up explaining nothing." Nonetheless, many consumer attitudes and their wine purchases are based on a language of 'terroir'.

    When one Googles the word 'terroir' many articles surface that provide many general 'terroir' categories, such as climate, soil, topography, grapevine genetics, human culture, and the microbiome of fermentation. Faced with these myriad factors, it is convenient to break 'terroir' into two broad realms: the physical, or vineyard site characteristics, and the sensory aspect of wine from a given site, Zoecklein (2019). Physical site characteristics with assigned  numeric values, calculated as 'natural terroir units' (NTUs), are used in some wine regions to assign value or rank to vineyard sites and their wines (Table 1). From the NTU list we consider: climate, soil and yield. Both climate and soil have been amply documented to drive all vine performance (Jackson and Lombard, 1993) and yield is important across all agriculture endeavors.   

Although climate is presented as single entity in the NTU listing, as it affects agriculture, inclusive of vineyards, climate is best understood on three levels (Figure 1): ‘microclimate’, the climate within the grapevine canopy (or any plant canopy), ‘mesoclimate’, within a particular vineyard, farm or agronomic field and ‘macroclimate’ or regional climate, categorized as either maritime or continental (Geiger, 1927, as cited in Patterson and Buechenstein, 2018). 

CATEGORY  ‘Natural Terroir Unit’	MAXIMUM VALUE
Location	600
Aspect	250
Altitude	150
Gradient	100
Soil	100
Microclimate	60
Varieties	150
Vine age	60
Vine density	50
Yield	150
Maintenance	100

Table 1. Physical parameters or Natural Terroir Units (NTUs), used to classify a vineyard site’s ‘terroir’ and the wine it is likely to produce. Adapted from, Carey (2001).

 

 

Figure 1. Three levels of climate impacting plants/grapevines.

    Next, lets briefly consider soil and its role in ‘terroir’. Notice that within the NTU list (Table 1) ‘aspect’ (compass direction) is ranked over soil, despite soil's geology and proven agronomic impact on most all agricultural crops. However, Van Leeuwen et al. (2004), elegantly investigated ‘terroir’ in Bordeaux, France by comparing yield and berry composition of three vineyards, all exposed to a similar climate and the planted to the same cultivar, Cabernet Franc, but, each having a distinct soil type (Figure 2). Van Leeuwen et al. found that the soil’s water holding capacity, contingent on its texture, was the factor with the greatest effect on vine vegetative growth that indirectly impacted berry composition, and finally, the wines from each site. In another soil-centric study in Australia, withholding irrigation water pre-fruit-set to veraison (onset of ripening: grapes soften and develop color, flavor and aroma), restricted vine uptake of nitrogen, and improved berry composition without significantly reducing Brix level (sugar %) or yield (White et al., 2007). Unsurprisingly to agrarians, these studies showed that water and its availability dependent on soil type, along with the mineral nutrient, nitrogen, are the main drivers of plant growth, including grapevines. These two components influenced by the vineyard soil, invariably and substantially, impact the physical realm and result of ‘terroir’.

 

Figure 2. Percentage of clay, loam, sand and gravel in the root zone of (A) gravelly soil, (B) clayey soil and (C) sandy soil. (Van Leeuwen et al., 2004).

    Next within the NTU list, consider that yield is assigned greater weight than ‘maintenance’, i.e., all viticultural operations: pruning, leaf removal, trellis design, fertilization, cultivation, cover crops, irrigation, and spraying. This ranking of yield over maintenance, is interesting in light of the widely cited and classic paper by Jackson and Lombard (1993), who review and explain the impact of site and viticultural operations, i.e. ‘maintenance’ on grape composition and yield, without mention of the word ‘terroir’. To this point of maintenance or cultural impact, Dr. Mark Matthews, (2015) presents several ‘terroir’ ‘beliefs’ that he classifies and explores as ‘myths’ and then systemically debunks. One of these myths is: ‘high yield equals low quality’ and its accompanying tenet: many small vines with a small yield is superior to few large vines with greater yield.

I have first-hand experience with this ‘tenet of terroir’. As a vineyard consultant working in the humid, southeastern US, I was presented with a vineyard planted to a ‘high-density’ European model, with meter x meter vine spacing and ~ 4,400 vines/acre. Research based recommendations for the eastern US at the time, were for a much wider row and vine spacing, with ~ 800 to 1000 vines/acre. The high-density planting presented problems: increased fungal disease, low yields, poor quality fruit (reduced light exposure and increased bunch rot), increased labor for: canopy management, mowing, spraying and harvest as ‘normal’ tractors could not navigate the ~ 39 in. rows (Figure 3).

  Figure 3. Meter x meter vineyards: Chablis France (left) and North Carolina, US (right).

    It was not my personal opinion, but peer-reviewed research (Intrieri and Filippetti, 2000) that informed my recommendation that two thirds of the rows, and every other vine within a row be removed, to achieve a ~9’x 6’ spacing and ~ 840 vines/acre. Fewer vines/acre actually increased yields (from 1 to 2 tons/acre the next year) and quality, reduced operating costs, and refuted the low yield = high quality ‘belief’. Obviously, this one case study does not explain the entire concept of ‘terroir’, but it did shed a degree of empirical light on one aspect of it…in that one place.

The second realm of ‘terroir’: sensory impact, has relatively recently been explained beyond the subjective, in a classic paper by Dr. Ann Noble, the first woman food scientist at UC Davis. Dr. Noble applied descriptive analysis and comparative statistics to compare and differentiate wines (Noble et al., 1984).

Term	Composition of reference standard
Berry (black/raspberry)	10 ml liquor from canned blackberries, 2-3 thawed frozen raspberries, 5-6 g strawberry jam, 5-6 g raspberry jam
Black currant (canned/ “Ribena”)	7-10 ml liquor from canned black currants, 2-4 ml Sainsbury’s black current drink
Synthetic fruit	5 ml cherryade (Corona drinks), 1 pear drop
Green bean/green olive	4-5 ml liquor from canned green olives, 8-10 ml liquor from canned green beans
Black pepper	4 particles black pepper (fine ground)
Raisin	10 raisins
Soy/ “Marmite”	0.5 ml soy sauce, 0.5-1 g “Marmite” yeast extract
Vanilla	0.25 ml vanilla flavoring essence
Phenolic/spicy	5-10 ul 4-ethyl guaiacol
Ethanolic	5 ml (950 ml liter-1) ethanol

Table 2. Aroma terms selected for the descriptive evaluation and composition of the reference standards created to define them (Noble et al., 1984).

Descriptive analysis protocol required that a trained a panel of tasters assess (describe) the wines (24 wines from four different Bordeaux producers) using commonly discovered and agreed upon aromas and flavors, benchmarked with common ‘reference’ standards (Table 2). The wines’ quality was further compared by certified Masters of Wine (MW). The major differences between the wines was in variation of the intensity of the ‘green bean/green olive’ character and astringency and bitterness by mouth, determined by canonical variates analysis (CVA). The wines did not differ between producers and MWs were unable to differentiate the wine’s quality.

Recently, wine writers and critics have taken to describing a ‘direct connection between wines and their terroir’, via the flavor descriptor referred to as ‘minerality’ (Maltman, 2013). Despite the physical difference between mineral compounds that occur in soil, and mineral nutrients that occur in grape juice and wine, many wine writers and winemakers, claim to taste the vineyard soil in wine. A wine’s ‘minerality’ is not only ‘detected’, but celebrated! What exactly are they tasting? For example, if the mineral nutrients of potassium, calcium or sodium actually occurred at levels within the human sensory threshold and thus, were detectable to the palate, they would likely be toxic! In this instance ‘minerality’ is a subjective descriptor, not an actual measurable factor. ‘Minerality’ may well exist…however, it is just not the case that actual mineral compounds are absorbed by the vine’s roots, transported to the grape berries, directly deposited in one’s wine glass and consequently are available and tasted as ‘minerality’ (Maltman, 2013). ‘Minerality’ then, as a descriptor, appears well-positioned to occupy the tension between the physical and sensory realms of terroir and that of unsubstantiated beliefs.

Obviously, there is something going on with winegrowing, wine consumption and “terroir”. Terroir’s factors, as defined by Seguin at the beginning of this essay, can be investigated and measured, wine is an agricultural product after all. However, few agricultural products have gods dedicated to them, as provided by the Greeks and Romans. There remains something unexplained about a wine’s ‘terroir’, something akin to Chinese acupuncture, or Polynesian ocean navigation, each of which is documented to actually ‘work’ (Patterson and Buechenstein, 2018). ‘Terroir’ as an overarching explanation of winegrowing seems to ‘work’ for many…and to those of us who doubt, question, test and document…it extends an invitation of exploration and discovery into what makes grapes transformed to wine so unique and special to us.

References:

1.  Carey, V.A., 2001. The Spatial Characterization of Natural Terroir Units for Viticulture in the Bottelaryberg-Simonsberg-Heiderberg Winegrowing Area. MS Thesis, University of Stellenbosch.

2.  Intrieri, C., and I. Filippetti. 2000. “Planting Density and Physiological Balance: Comparing Approaches to European Viticulture in the 21^st Century.” Proceedings of the American Society of Enology and Viticulture 50^th Anniversary Annual Meeting, June 19-23, 2000 Seattle, Washington, 296-308.

3.  Jackson, D. and P. Lombard. 1993. Environmental and management practices affecting grape composition and wine quality—a review. Amer. J. Enol. Vitic. 44: 409-430.

4.   Maltman, A. 2013. Minerality in wine: a geological perspective. J. Wine Res. 24:169-181.

5.  Matthews, M. 2015. In, Terroir and Other Myths of Winegrowing., Univ. of Calif. Press, Oakland, CA.

6.   Morris, R., 2018. Does terroir matter? https://www.winemag.com/2018/11/13/does-terroir-matter/

7.  Noble, A.C., A. A. Williams, and S.P. Langron. 1984. Descriptive analysis and quality ratings of 1976 wines from four Bordeaux communes. J. Sci. Food Agric. 35:88-98.

8.   Patterson, T. and J. Buechsenstein. 2018. In, Wine and Place., Univ. of Calif. Press, Oakland, CA.

9.   Seguin, G. 1986. ‘Terroirs’ and pedology of vinegrowing, Experientia, 42:861–873.

10. Van Leeuwen, C., Friant, Ph., Chone, X., Tre’goat, O., Koundouras, S. and Dubourdieu, D. 2004. The influence of climate, soil and cultivar on terroir. Amer. J. Enol.Vitic., 55:207-217.

11. White, R., Balanchandra, L., Edis, R. and D. Chen. 2007. The soil component of terroir. J. Int. Sci. Vigne Vin. 41: 9-18.

12. Zoecklein, B. 2019. What defines your wines? Wine Business Monthly, Dec. 62-69. www.winebusiness.com

Suggested reading:

1.   Keller, M. 2010. In, The Science of Grapevines: Anatomy and Physiology., Academic Press, Burlington, MA.

2.  Van Leeuwen, C. and G. Seguin. 2006. The concept of terroir in viticulture. J. Wine Res. 17:1-10.

3.  Van Leeuwen, C., Roby, J-P., and L. Rességuier. 2018. Soil-related terroir factors: a review. Oeno-one. 52: https://oeno-one.eu/article/view/2208

4.  White, R. 2020. The value of soil knowledge in understanding wine terroir. Front. Environ. Sci. 8:1-6. https://www.frontiersin.org/articles/10.3389/fenvs.2020.00012/full