Katherine Cole on Black Chardonnay

My husband forwarded me this link Meet Black Chardonnay written by Katherine Cole (author of the book Voodoo Vintners). Both of us read it with a lot of interest. Since we vinified our first small batch of Chardonnay this year, we know that turning Chardonnay grapes into wine can be tricky if we want our wine to age well.
The question is: reductive or oxidative strategy?
Professor Denis Dubourdieu and Dr. Valérie Lavigne researched the recent propensity of Chardonnay in Burgundy to succumb to premature oxidation and I wrote about their research in a blogpost that I called How to Prevent Premox in White Wines.
Answer: Keep it reductive. So consequently, winemakers struggled mightily to keep oxygen out of their winemaking regime. Press gently, keep oxygen away from the must!

Now, however, Katherine Cole writes about the black Chardonnay movement. This is NOT the "benign oxidation" browning, that our class reached a consensus on, as a good thing, in our online U.C. Davis course while reading and discussing the seminal article written by V. Schneider called Must Hyperoxidation: A Review.
In a technique used in Burgundy some 60, 70 or 80 years ago on Chardonnay, you must crush, grind, shred and hard press the resultant pulp in order to get this black must. This heavy handed treatment removes those phenols that cause astringency and bitterness as a precipitate, leaving the juice clear. It also removes phenols that become prone to browning through oxidation.
This technique is being practiced by winemakers in Oregon with amazing results. My husband looked up OO Wines that is using this methodology on their Chardonnay, but it cost $65.00, a little too rich for our tastes. I did try to convince him that we needed to purchase a bottle for "research purposes".

References:
1. Katherine, Cole, Meet Black Chardonnay, SevenFiftyDaily, August 3, 2017.
2. V. Schneider, Must Hyperoxidation: A Review, Am. J. Enol. Vitic., Vol. 49, No. 1, 1998.

2014 Paumanok Chenin Blanc Minimalist and 2015 Millton Chenin Blanc

Recently, we had our friends over for oysters from Harmony Sea Farm. These oysters are grown right in our backyard by Garrett and Sally Timmons. We got to taste their first harvest!

There is nothing better to pair with oysters than Chenin Blanc and we had 2 exquisite examples. We began with the 2014 Paumanok Chenin Blanc Minimalist. The back of the label is where you will find the vintage information as well as vinification information. Only unblemished, select clusters of Chenin Blanc from the vineyard planted in 1982 (35 year old vines!) were hand harvested and whole cluster pressed. Spontaneous fermentation began in stainless steel barrels and the wine was aged for 6 months. There were only 84 cases of 2014 Minimalist Chenin Blanc made. We heard an interesting story from Charles Massoud when we visited the winery recently. Charles mentioned that the Chenin Blanc was initially planted to blend with Chardonnay. But, Chenin Blanc, (as we found out) is one of those white varietals that doesn't really play well with other varietals in a blend and why would anyone want to dilute Chenin Blanc with Chardonnay!

The next wine that we opened was a 2015 Millton Chenin Blanc that our friends brought home from their sojourn to New Zealand. The Paumanok and the Millton could not have been more different on the palate! We immediately picked out the oak notes on the palate, slightly muted fruit and acidity and overall creamier mouthfeel. This Chenin Blanc was vinified in a totally different way from the Paumanok Chenin Blanc in demi-muids (large 600 litre oak barrels) as well as in stainless steel tanks. The notes from the winemaker mentions that up to four selections are made in the vineyard. The grapes are hand harvested, destemmed and crushed and the juice is allowed to settle. The fine sediment is kept as nutrients for fermentation. This wine had a total acidity (TA) of 7.5 g/L, pH of 3.33, alcohol content, 12.5% and residual sugar measuring 6.2 g/L.
Both wines were deliciously different and both were very much appreciated with the oysters. As we moved on to our second course of salad with bread and cheeses, the wines paired well with the cheeses too, providing for a wonderful degustation with friends!

Happy Thanksgiving: Something to Gnaw On

Here is a pre-Thanksgiving blogpost. I am currently reading a review called Origins of Grape and Wine Aroma. Part 1. Chemical Components and Viticultural Impacts that appeared in 2014 in the American Journal of Enology and Viticulture. It is 24 pages long so, I've been plodding along and trying to digest the review in small bites.
This morning, I came upon a paragraph that is almost incomprehensible by a lay person. I reproduce it below:
          Methional concentrations increase in white wines exposed to           elevated temperatures and oxygen. Under these conditions, the           compound is produced via a Strecker degradation of methionine to           methional in the presence of a dicarbonyl compound or via direct           peroxidation of methionol.
Whaaaaat?
Fortunately, my husband who is a chemist was sitting across from me, drinking his morning coffee, and I asked him do you know what a "Strecker degredation" is? He said, "sure, is that an oxidation?" (Close but no cigar!) Back in the days of taking organic chemistry, there were certain "name reactions" that one could memorize. So, here is my take on what the above paragraph translates into in organic chemistry terms.

So, the diagram above can be captioned: In the presence of a compound with 2 carbonyl groups, the amino acid methionine can react with one of the carbonyl groups forming an unstable intermediate. With the incorporation of 2 molecules of water, the unstable intermediate results in the formation of ammonia, carbon dioxide and methional.
What is wrong with having methional in white wine? The smell for one thing is of "cooked vegetables". Methional is also thermally unstable and undergoes a retro-Michael reaction that leads to the wet dog or wet wool smell in wine that comes from methyl mercaptan and acrolein.
Here is hoping that your Thanksgiving is a wonderful one with wines innocent of Strecker degradation and retro-Michael products. Cheers!
References:
1. Wil Konings, ‎Otto Kuipers, ‎O.P. Kuipers, Lactic Acid Bacteria: Genetics, Metabolism and Applications, 1999, pg. 250.

New Tab: White Winemaking

Today, I spent a few hours collating all of the blogposts on "white winemaking" and created a new tab:

Under that tab, you can find all of the postings related to "white winemaking":
How Many Grapes Does It Take to Make a Bottle of Wine
Making White Wine
White Wine Production Theory and Practice
To Inoculate or Not, that is the Question
Skin Contact for White Wines
Reductive Regime vs Oxidative Regime for White Wine Making
Rehydrating and Tempering Yeast
Benefits of Low Temperature Fermentation
Sur Lie Aging of Wine
Diacetyl Formation

White Winemaking Chemistry
Hyperoxidation Revisited
How to Prevent Premox in White Wines
Chemical Marker Sotolon Found in Premox Wines
Strategies to Manage Dissolved Oxygen
Post-Bottling Aroma Defects

I will keep adding to this tab as necessary. I hope it is useful to you!

Sur Lie Aging of Wine

We were able to make a few cases of wine from our 2016 vintage of Chenin Blanc this year. We are still bottling in half bottles, 375 mL so that we can make the most of our limited production. Yes, our wines are that "dear". So far, we have made 2 different styles of Chenin Blanc in 2015, a dry style we call "sec" and a style with sweet juice added back prior to bottling, a technique called "süssreserve" and in 2016 we left the wine on lees. Here is a tabular recap of what we actually bottled in 2015 and 2016:

Vintage	# 750mL Bottles	# 375mL Bottles	Style
2015	8	9	Sec
2015	4	10	Sussreserve
2016	12	27	Sur lie

On Thursday, we took a trip over to Long Island to visit Charles and Kareem Massoud at Paumanok Vneyards to have them give us feedback on our 2016 vintage. For our 2016 Vintage, we left our wine sur lie for approximately 10 months. What does sur lie do? It gives the wine a certain mouthfeel and flavor that Charles picked up on immediately!
At the end of fermentation, yeast and bacteria become inactive and settle out to the bottom of the fermentation tank. If the lees are fine in character without negative sulfur compounds, leaving the wine on this precipitated material can be beneficial. During this time, the yeast cell wall breaks open in a process called "autolysis", releasing mannoproteins and polysaccharides.

Sur lie aging accomplishes the following¹:

• enhances the structure and mouthfeel of a wine
• gives the wine extra body (an impact of polysaccharides on astringency)
• increases the aromatic complexity, flavour/aroma depth and length of the wine
• absorbs oxygen, assisting in maintaining a slow and controlled oxidation during wine maturation

Sur lie is not for all wine styles. But, with sur lie aging, we feel we have a new "tool" in our winemaking to call upon when necessitated by the vintage.
References:
1. Ben Rotter, Sur Lie and Bâtonnage, Improved Winemaking.
2. MoreWine!, Sur-Lie ageing.
2. Marta Dizy, Linda F. Bisson, Proteolytic Activity of Yeast Strains During Grape Juice Fermentation, American Journal of Enology and Viticulture, Jan 2000, 51 (2) 155-167.

8,000 Year Old Wine

My husband recently pointed me to an article that he saw on NPR about the discovery of the 8,000 year old wine from Georgia. In the previous blog Comparison of Wine to Music, Pretorius' timeline lists Georgia as one of the ancestral locations of grape growing.
In research done by McGovern et al. and available online Early Neolithic wine of Georgia in the South Caucasus provides details on how a determination was made to establish that winemaking was in fact occurring in the early Neolithic period (ca. 6,000–5,000 BC) in the region now known as Georgia.
One of the earliest Neolithic cultures occupying the modern regions of South Georgia, Northern Armenia and Western Azerbaijan in the South Caucus is the "Shulaveri-Shomu Tepe Culture". Imagine living nearly 8,000 years ago during the Neolithic revolution when the “founder crops” of barley, einkorn wheat, emmer wheat, chickpea, pea, lentil, flax, and bitter vetch were being cultivated, harvested and stored. This assurance of a food source allowed for advances in the arts and crafts, such as architecture, weaving, dyeing, stone working, woodworking and wine making.
These ancestors possibly saw the domestication of the wild Eurasian grape (Vitis vinifera sp. sylvestris), resulting in V. vinifera sp. vinifera, being hermaphroditic, didn't leave pollination to chance and provided a reliable source of grapes.

Previously, McGovern reported on the Hajji Firuz Tepe region as being the site of early winemaking based on traces of tartaric acid that could be identified on clay sherds.
In this article, wine jars from as early as ca. 6,000 BC have been confirmed for Gadachrili and Shulaveri, preceding the Hajji Firuz jars by half a millennium! In order to do this, the team analyzed five base sherds from Gadachrili and three from Shulaveri. The presence of tartaric acid and other organic acids such as malic, succinic, and citric acids was crucial in establishing the original presence of wine in these vessel sherds.
The next time you pick up a glass of wine, give a nod to the Neolithic people of Georgia who, during the great Neolithic revolution took the wild Eurasian grape (Vitis vinifera sp. sylvestris) and domesticated it, resulting in V. vinifera sp. vinifera becoming the basis of our current “wine culture”.
References:
1. Patrick McGovern, et al., Early Neolithic wine of Georgia in the South Caucasus, PNAS 2017 : 1714728114v1-201714728. 2. David Maghradze, et al., Grape and wine culture in Georgia, the South Caucasus, BIO Web of Conferences 7, 03027 (2016), 39th World Congress of Vine and Wine.

Comparison of Wine to Music

I came upon this beautifully written and understandable article by Isak S. Pretorius called Conducting Wine Symphonics with the Aid of Yeast Genomics. Given my penchant for pictures, this article is a veritable goldmine of amazing artwork all while explaining winemaking and it's analogy to great music. Although it is a somewhat long article, you will want to linger over the illustrations and absorb all of the information presented in this article.
Here is how Pretorius depicts the spread and timeline of grape growing and winemaking.

From the beginning to the end, this article masterfully provides a journey into:

• the spread of viticulture and enology
• determining quality and value of a wine
• outlining the difference between white and red wine making
• providing a comprehensive treatment of yeasts and bacteria that can contribute to fermentation derived compounds

Here is how Pretorious depicts the various styles of yeast fermentation:

I'm glad I stumbled on this article and I hope you enjoy it as much as I did.
References:
1. Isak S. Pretorius, Conducting Wine Symphonics with the Aid of Yeast Genomics, Beverages, 2016, 2(4), 36.

2014 Etienne Sauzet Bourgogne

We had this 2014 Etienne Sauzet Bourgogne (Chardonnay). We are in research mode, trying to learn what style of Chardonnay we really like and how vintners make the style that we like, so a lot of Chardonnay imbibing is in our future. We really liked this Etienne Sauzet Bourgogne. Chardonnay is one of those varieties that is very malleable in a winemaker's hand. However, there are two styles that Chardonnay drinkers gravitate toward:¹

• Style A: a more “traditional/ oaky” Chardonnay style, marked by “caramel”, “butter”, “honey”, and “oak” attributes
• Style B (a “crisp/fruity” style, with “tropical fruit”, “melon”, and “green apple” notes

Would you believe that this Sauzet had both flavor profiles, not too heavy handed on the traditional oaky, while having some of the tropical fruit. How did they do that? I searched on the Internet but information was very sparse. My husband, on the other hand had taken out a hard cover book that we have written by Remington Norman and Charles Taylor MW, called The Great Domaines of Burgundy, Third Edition, which had a short write up of Etienne Sauzet.
Etienne Sauzet began with 3 ha in Puligny-Montrachet at the turn of the 1900s and continued to add more vineyard land. Tragically, in 1989, Etienne's daughter decided to divide the vineyards, for tax reasons between her three children, but did not stipulate that the domain remain intact!
In 1974, Gérard Boudot, who is married to Etienne Sauzet's grand-daughter, Jeanine, succeeded Etienne Sauzet, with one third of the original domaine intact, including the grand cru holding of Bâtard-Montrachet.
The grapes that go into the Bourgogne is a blend of wine fermented in stainless steel vats and wine that is barrel fermented this leads to a wine that is full and ripe with good length. This may explain why the Bourgogne still has fruit flavors but also has oak notes.
I concur, this is my new favorite Chardonnay.
Once I fine-tuned my search, I did find a site that provided more detail on the care that Gérard Boudot takes in the vineyard and how they harvest and make their wines. If you're interested in learning more, check this out this site: VinConnect: Etienne Sauzet.
References:
1. Gambetta JM, Bastian SEP, Cozzolino D and Jeffery DW., Factors influencing the aroma composition of Chardonnay wines, 2014, J Agric Food Chem 62:6512–6534.
2. Remington Norman and Charles Taylor MW, The Great Domaines of Burgundy, Sterling Publishing, New York, London, Third Edition, 2010.

Bottling Our Chenin Pét-Nat

One of the benefits of this season's harvest is that we had a little more Chenin Blanc juice than we expected, so my husband decided to make a few bottles of Pét-Nat, or pétillant naturel aka méthode ancestrale. To do this, he had to carefully monitor the sugar levels in the 10 liter keg to ensure that we had enough sugar to allow the fermentation to continue after we bottled the juice in champagne style bottles.
In reading more about this style, I came upon the online Esquire site that had an article called The 10 Best Pét-Nat Wines Under $40. This is what the article said: If Champagne is Rolex, pét-nat is Swatch. I think that is pretty clever.

To make our pét-nat, my husband made sure the starting wine had approximately 2-3% (20-30 grams/liter) sugar which will hopefully transform into 3-5 atmospheres of entrained carbon dioxide. So, on November 3, we racked the juice from our 10 liter keg into 9 champagne style bottles which we capped with a crown cap. The great thing about pét-nat is that there is no fining or filtering involved once the product is made in the bottle. So this sparkling will be a little hazy in the glass. Crossing fingers and hoping for fermentation to continue in the bottle.

Chardonnay: Aging Derived Compounds

This is the third (possibly last) of the series of blogposts on Factors influencing the aroma composition of Chardonnay wines. My brain is tuned to looking at pictures which gives me a better understanding when facts are provided in that format so I created illustrations from the tables that summarized the compounds that come from (1) the grape, (2) fermentation and (3) aging.
Here are the compounds that come from wine aging.

Aging in oak barrels leads to wine compounds that can arise from:

• extraction of oak volatiles
• contact with lees
• processes associated with the “low oxidation” conditions
• microoxygenation

The most important compounds released by oak into the wine are the cis- and trans-oak lactones. The presence of these lactones is affected by the age, origin, and volume of the barrel.
Benzenemethanethiol (BM) and 2-furanmethanethiol (FFT) at concentrations above the perception threshold were found to increase during aging. BM has been described as contributing “flinty” and “smoky” notes and may be related to Chardonnay's “mineral” character. FFT confers a strong “roast coffee” aroma and is formed from furfural released by oak barrels and hydrogen sulfide during alcoholic fermentation. BM and FFT were found to increase during aging.
Other compounds derived from aging in oak barrels that confer Chardonnay "typicity" include guaiacol, 4-ethylphenol, 4-ethylguaiacol, 4-vinylphenol, vanillin, methyl vanillate, and 5-methylfurfural. Furfural formed in oak during coopering was extracted during fermentation and aging in barrels.
In general, “young wine”, “fruity”, and “floral” characters decrease rapidly in white wine during aging, mostly due to loss of acetate esters and ethyl esters of short-chain fatty acids transforming into forms with less-intense aromas such as α-terpineol.
In contrast, ethyl acetate, diethyl succinate, ethyl lactate, ethyl 2-furoate, ethyl 2-phenylacetate, and ethyl 2-methylbutanoate were more abundant in the older wines.
With that, this concludes the three part odyssey into aroma and flavor compounds in Chardonnay wines. Thanks for sticking around!
References:
1. Gambetta JM, Bastian SEP, Cozzolino D and Jeffery DW., Factors influencing the aroma composition of Chardonnay wines, 2014, J Agric Food Chem 62:6512–6534.
Illustration created from Table 4. Odorants Derived from Oak Contact or Formed during Aging That Are Important to the Typicity of Chardonnay Wines, pg. 6516 of the reference above.
2. Joanna M. Gambetta, Leigh M. Schmidtke, Jiaming Wang, Daniel Cozzolino, Susan E.P. Bastian, David W. Jeffery, Relating Expert Quality Ratings of Australian Chardonnay Wines to Volatile Composition and Production Method American Journal of Enology and Viticulture Jan 2017, 68 (1) 39-48; DOI: 10.5344/ajev.2016.16058

Chardonnay: Fermentation Derived Compounds

Following up on the blogpost Chardonnay: Grape Derived Compounds is today's blog on fermentation derived compounds. The fermentation derived compounds come from the primary fermentation with yeast and the secondary fermentation with malolactic bacteria, yielding many compounds that contribute to the aroma and flavor profile of Chardonnay. Yeasts are not only important in the transformation of sugar to alcohol, but they are also important in the de novo synthesis of important sensory compounds.
During primary fermentation, esters are formed in excess by yeast metabolism and are responsible for “fruity” and “floral” aromas. Acetates are synthesized at higher concentrations than ethyl esters, and the ratio between both, as well as the concentration at which acetates are produced, is affected particularly by:

• fermentation temperature
• must nutrient content
• yeast strain

As the above illustration shows, there are considerably more compounds derived from fermentation than what the Chardonnay grape provides. The most relevant esters for unwooded Chardonnay aroma appear to be ethyl hexanoate, ethyl octanoate, ethyl decanoate, ethyl 2-methylpropanoate, ethyl 2-methylbutanoate, ethyl 3-methylbutanoate, hexyl acetate, 2-methylbutyl acetate, and 3-methylbutyl acetate. These compounds located on the left side of the illustration contribute floral, berry, red fruit, green apple, strawberry, and other fruity aromas. Esters formed during alcoholic fermentation constitute one of the main groups of sensorially important compounds in Chardonnay.
When secondary or malolactic fermentation (MLF) is carried out on Chardonnay to transform malic acid to lactic acid, this also produces diacetyl and acetoin which contributes the typical “buttery”, “hazelnut”, and “fresh bread” notes.
Next up, Aging Derived Compounds.
Note November 3, 2017: The illustration that was initially on this post has been updated to correct spelling errors. It has also been organized according to chemical class.
References:
1. Gambetta JM, Bastian SEP, Cozzolino D and Jeffery DW., Factors influencing the aroma composition of Chardonnay wines, 2014, J Agric Food Chem 62:6512–6534.
Illustration created from Table 3. Characteristics of Odorants Important to Chardonnay Wine Typicity Formed during Alcoholic and Malolactic Fermentation, pg. 6514-6515 of the reference above.
2. Joanna M. Gambetta, Leigh M. Schmidtke, Jiaming Wang, Daniel Cozzolino, Susan E.P. Bastian, David W. Jeffery, Relating Expert Quality Ratings of Australian Chardonnay Wines to Volatile Composition and Production Method American Journal of Enology and Viticulture Jan 2017, 68 (1) 39-48; DOI: 10.5344/ajev.2016.16058