Diamonds May Not Be a Wine's Best Friend

Winter is a bit of a slow time for the winemaker. The grapes have been harvested, the press has been cleaned and put away, and the wine has been made. That means my job is done, right? Well, it’s a little easier right now and not as frantic, but certainly not done. Right now, all the wines we made from the 2021 harvest are aging. Whites are aging in stainless steel tanks and reds are aging in oak barrels. But there is another process going on for the white wines: cold stabilization. 

To explain this, we need to look at the grapes. All wine-making grapes have naturally occurring tartaric acid in them. Much like citric acid gives lemons and limes their tartness, tartaric acid gives the wine its own unique tartness. That tartness is desirable and important for balance in the finished wine. However, the wine can only hold so much tartaric acid, or tartrates, in suspension. If there is too much in the solution, it will start to precipitate out and form crystals. These crystals are affectionately referred to as wine diamonds. The cold stabilization process forces the wine to “give up” its excess tartrates. We do this by chilling the wine down to about 30°F for about 2-3 weeks. This causes the excess tartaric acid to solidify out of the solution. This process is mostly cosmetic for the wine, it does not change its flavor or aromas. If cold stabilization did not happen, or did not finish, you may find wine diamonds in the bottom of the bottle you just pulled out of the fridge. If you do not know what they are, you might think that there was something wrong with the wine. If you do find a bottle with some crystals in it, rest assured that it is safe to drink. The tartrates themselves do not taste like much but are a little gritty and not very pleasing texture-wise. Pour the bottle of wine slowly to avoid getting them in your glass or pour the wine through a strainer. 

Wine diamonds can happen in both red and white wine, but we typically only cold stabilize the white wines. One of the biggest reasons is that white wines are ready to bottle sooner than red wine. Tartrates will precipitate out naturally over time. For a glass of red wine, this means that as they are aging in their barrels, they are releasing their wine diamonds and one year or so is usually plenty of time for tartrates to solidify. Another big reason is that white wines are served chilled, and chilling releases the tartaric acid crystals. A red wine that is never chilled may never have its excess tartaric acid precipitate out of solution.  

Although winter is kind of a slow boring time in the cellar, it is the best time for cold stabilization. All this cold weather means that our tank chiller doesn’t have to work so hard to keep the wine at the right temperature. But it also means that I’m a lot colder while I work.

 

What Happens to the Vines During Winter?

Spring and summer are where all the action is for grapevines but fall and winter are equally as important for the well-being of the vine, albeit a little boring at times. Like deciduous trees, grapevines lose their leaves in the fall, the sap travels primarily to the roots, and the vine goes dormant. Another way of looking at it is to say that the vine is sleeping.

During this time, the vine is not producing shoots, leaves, or grapes. Instead, it is saving up all its energy for the coming spring where it will once again burst forth with grapey goodness. But just because the vines are asleep doesn’t mean that grape growers can take a break. With all the leaves gone, winter is a great time to assess the health of the vines. It is easier to see cordons and shoots and how they grew during the spring and summer will influence how the grape grower will prune back for next year. Excess rain during the fall could mean that early application of fungicides is necessary. Another thing to look out for is those pesky freezes. Because the sap has moved to the roots, a fully dormant vine is fairly well protected from freezes and cold weather. At least it is in regions where the cold weather is more predictable. 

One of the challenges of grape growing in Texas is the wonky weather. Because most parts of Texas rarely see temperatures below freezing for an extended period of time, the grapevines do not always go fully dormant. An advantage of this would be that the vine expends less of its energy stores “waking up” in the spring, thus having more energy to make good grapes. The disadvantage of this is that if Texas does have a snowpocalypse the sap that is left in the trunk and cordons could freeze. This freezing sap expands and damages the cellular structure of the vine. The damage could be minor, and the vine may be able to heal on its own or it could be catastrophic, and the vine could die. There is no rest for the grape grower, and we can not make great wine without happy healthy grapevines. 

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The Story of Lost Oak

The Story of Lost Oak
The wine, the business, the family 

In the spirit of the holidays, we would like to spread some cheer and tell the classic tale of Lost Oak to you!

The mind behind Lost Oak Winery is founder, Gene Estes. His sense of passion for the wine industry and dedication to growing wines has been the backbone of Lost Oak Winery. Gene Estes was born in Abilene, Texas. After returning from Vietnam in 1966, Gene attended Texas Tech University and graduated with a Master of Science degree in Microbiology. Gene had a 40-year career in the pharmaceutical industry. He studied Viticulture via correspondence and had the good fortune to learn from native growers in Alsace France during an assignment in his final years at Alcon. 

The first Lost Oak vineyard was planted in 1998 and started out as an experimental vineyard, growing many varieties to observe. The first varietals planted were Riesling, Gewurztraminer, Leon Millot, Chambourcin, Chardonel, and Shiraz. “Making a great wine requires superior wine grapes, lots of devotion, time, and sacrifice,” Gene said. Today, the estate vineyard focuses on Shiraz. 

In the last few years, Lost Oak has grown into what it is today due in large part to Gene’s daughter, Roxanne who joined the business in early 2007. Roxanne’s emphasis on events and her marketing and people skills have been key to this success. From Tasting Room to President, she can be credited with growing Lost Oak Winery in the last 13 years, developing a robust event business, and helping Lost Oak to expand into the Hill Country. 

 

From the Wine Nerd

Winemaking can be romantic and fun, but it’s also hard and dirty work. One of my favorite dirty jobs around the production barn is cap management. No, it’s not trying on different hats and posing for selfies with the barrels.

Let’s start with the cap and why it needs managing. The cap is a layer of grape skins and seeds that forms on the top of fermenting red wine. The yeast eats the sugars in the grape juice and produces CO₂. The CO₂ pushes the skins and seeds to the top of the fermenting juice and then you get a cap. We don’t want that cap to stay there, we want it all mixed up with the fermenting juice for better color, aroma, and flavor extraction.

There are different techniques we can use to get this cap all stirred up. The first is called a punch down. We use a tool to punch the cap back down and stir it all up. Large fermentation tanks are too big to use the punch down method, so we pump-over.  This means we pump the fermenting juice from the bottom of the tank and spray it on top of the cap to mix it up.

The last method is delestage (rhymes with sell-best-lodge). This is like pump over except we pump the fermenting juice into a different tank, allowing the cap to fall all the way to the bottom. We let the cap settle and then pump the juice back on top of the cap. It is a messy job and it one that cannot be ignored; it must be done every day. As long as we have red wines fermenting, I’ll be here managing the caps… and taking the occasional selfie. 

 

Harvest is Happening!

It’s hot out, and in Texas that means it is time for the grapes to come off the vine. We started harvesting on our property on July 24th! Now we are well into September and all the Lost Oak grapes are off the vines and being turned into wine.

So, how was the harvest? Going into spring the weather was cool and there were wonderful pop-up rains with no hail. The vines were bursting with buds and looking happy and healthy. But as the grapes matured the reality of “snowmageddon” started to set in.  Turns out, it affected the vines a little more than we thought it was going to. Our yields were down… way down. No Blanc du Bois at all! 

But it is not all doom and gloom. Our vines may not have produced what we wanted them to, but they survived, and we are sure that this will only make them stronger. We are also working closely with our growers in the High Plains, so we won’t be lacking for grapes around here. We may see less of some of our favorites this year, but it may also be a great opportunity to pick up some new favorites…wink-wink. 

Estate Vineyards Harvest

In 1995, I bought the property on which Lost Oak Winery is located.  My main decision for buying this property was the excellent soil and drainage profile for growing wine grapes.  I then planted our first Estate vineyard in 1998. That was 22 years ago, and I did not know which grape varieties would do best on this tract of land, so I planted 7 different varieties. Shiraz performed the best by far so when I planted our second Estate vineyard, we chose to plant mostly Shiraz and Blanc DuBois.  Blanc DuBois also performed very well so we decided to pull up all of the other varieties and re-plant only Blanc DuBois and Shiraz. 

The vineyards at Lost Oak normally have bud-break between late March to early April, and “bloom” in late April.  Bloom is when the tiny white flowers drop, and the small fruit clusters appear.  This is followed by verasion which normally occurs in late June to early July.  Veraison is when the red grapes turn from green to red and the white varieties from green to yellow / white.

 

Right after veraison, we start measuring the sugar levels of the grapes. We continue measuring
until we are confident of the proposed harvest date. Normally we harvest our Blanc DuBois first
– around the last week of July. Our Shiraz is usually harvested around the second week of
August. The sugar levels are determined using a refractometer. It‘s like looking through a small
telescope where one gets a visual reading of the color change on a scale of 0 to 30. We refer to
this as degrees Brix. Although this is the most important factor in determining harvest date,
there are several other very important factors that also must be considered:

• a. Seed color (seeds need to be yellow brown to dark brown
• b. Seed texture (seeds need to be crunchy when you bite down on them)
• c. Shrivel (the grape skins need to be slightly shriveled)

These are all important signs of ripeness which, if adhered to, will give maximum flavor and
aroma when converted to wine. Therefore, if we pick too early or too late we “miss the target”.

We use volunteers to help us harvest our Estate vineyards because it is a manual process
requiring pruning shears, buckets, and teamwork. Normally, we have a substantial list of
customers, wine club members, and neighbors who want to help. We coordinate with them by
emails starting 2 weeks in advance of predicted harvest dates and then give final notice 48
hours before the actual harvest. The grapes tell us when they are ready, which means
harvest is never scheduled for convenience even if it is on a weekday when most people have
to work, or if there is a predicted chance of rain. Each year it is exciting to see the grapes
harvested and the next cycle of wine-making begin.