This article will focus on the various popular fermentation techniques. We want to know the role and effects of each technology, understand the technical theory and try to find the fermentation technology that the winemakers have been using for the next ten years.
For the past three decades, the California brewing industry has witnessed the ups and downs of fermentation technology. In the early 1980s, winemakers digested white wines and sometimes oxidized white grape juice before fermentation. Red grapes are usually picked when the Brix reaches 24 degrees, then pressed into a fermenter, treated with sulfur dioxide, tartaric acid, and added to the yeast the next morning. Centrifuges and rotary fermentation tanks are popular during the brewing process. For many years, people have used the extended impregnation method before the fermentation of grapes, and recently the popular cold soaking method has begun.
This article will focus on the various popular fermentation techniques. We want to know the role and effects of each technology, understand the technical theory and try to find the fermentation technology that the winemakers have been using for the next ten years.
We invite a number of winemakers from different backgrounds: from large wineries to small wineries, the wines range from sparkling wines to liqueurs and even non-alcoholic, de-alcoholic wines. They provide consulting services for many foreign wineries. The interviews cover not only the application of fermentation technology, but also the embarrassment of winemakers in choosing these fermentation technologies.
Biography
Professor OdedShakked came to Israel from the University of Davis in 1984 to study winemaking. After graduating, Oude worked in the Jordan family winery for 18 years of liqueur and sparkling wine. In 1998, he started his own Longboard winery, and now the winery produces 10,000 boxes a year.
Ray Kaufman comes from the Sonoma grape growing region. I started working as a part-time filling worker on the filling line, then worked in many wine cellars and finally found a suitable job at Kenwood Winery. Ray moved to LaurelGlen twenty years ago and is now working with Patrick Campbell to produce wine in 17 countries.
Barry Gnekow majored in biochemistry at Davis University and graduated in 1976. Barry was the assistant winemaker at J. Lohr Winery and worked as a manager for three years in the sales department. In 1990 he pioneered the production of alcohol-free wines using reverse osmosis.
Why use cold soaking to make wine?
Ray: 15 years ago, we started to ferment with native native yeast. Cold soaking is a natural part of these fermentation processes. I don't think there is any harm in the cold soaking method, but it helps to slow down the fermentation process. The fermentation process depends on the temperature at which the berries are placed, the temperature is too high and needs to be cooled immediately.
The cold soaking method is also applicable to the brewing of Cabernet. For coloring and extraction, we must combine cold soaking with the use of native yeast. In addition, cold soaking is a good way to prevent over-extraction.
Barry: I try to test the cold soak in as many ways as possible. For red grapes picked at different times, as well as the size of the fermenter, sometimes cold soaking is not feasible. If you pick grapes at night and start brewing at low temperatures, you don't need cold soak. Before the start of fermentation, the juice is soaked with the peel so that some reactions can be carried out without the influence of microbial activity. This will give the wine a deeper color and a better taste, which I think is more suitable for Pinot Noir.
Aude: There is a theory that the fermentation process should be combined with back extraction methods, especially when adding grape stems. If the fermenter containing the high-quality wine is doped with grape stalks, it will definitely entrain the juice of the grape stems.
However, cold soaking can make the extraction more complete without the special smell of grape stalks. Therefore, cold soaking in the early stage will make the extraction different.
For me, cold soaking is a balancing process. I will not cold soak the higher temperature fruit. If you can pick low-temperature fruit from the vineyard, I will put it in the tank without having to wait for it, waiting for its slow fermentation. If the temperature of the fruit is too high and there is really no good way to cool it, then only cold soaking can be used. In fact, I would rather add yeast directly to the fermentation.
Cold soaking can extend the fermentation time, which is not harmful to the wine itself. However, according to experience, the advantage of cold soaking method lasts for a short time, as is the case with other enzymes. In the early days we can see the difference between cold and non-cold-brewed wines, but after three years these differences will disappear on their own.
Barry: Many issues need to be prioritized during the winemaking process. This year we have adopted very mature wines. If the wines purchased by the winery are of high temperature, they cannot be cooled down to the size of the steel cans, or they can be stored for 4 to 5 days even if conditions permit, so there is no need for cold soaking.
Odd: I also think that the source of berries and the growers are more important than whether they are cold soaked. If time is sufficient, the winery space is large enough, and the temperature of the grapes is low, I am willing to carry out cold soaking, especially during the brewing of Pinot Noir, as this can delay the fermentation process. Without these conditions, fermentation will begin within a few days.
Ray: I don't make Pinot Noir, and there is no color extraction problem in Cabernet's brewing. But after cold soaking, the grape juice will bind tightly to the peel. This is definitely helpful for the Pinot Noir wines that are pursuing color.
Aude: I noticed that after the cultivation of Dijon cloned grapes, the color of the berries has changed a lot. The Wine Business has a price change of 800 yuan for the whole year. I also used tannic acid, SO2, and other treatments during cold soaking, but I never found that the color would look better just because of cold soaking. there has never been!
When do you use tannic acid? What is the role of tannic acid?
Aude: I think that when brewing Pinot Noir, adding tannic acid to the pulp can stabilize the color as soon as possible. In addition, tannic acid can also enhance the middle taste.
Barry: I used tannic acid four or five years ago and basically eliminated it. Instead of unbaked French oak chips. I have tried adding tannins in places with low tannic acid content, which has also been added in the process of brewing Pinot Noir, but these are not as effective as picking ripe berries.
I like to see the effect of tannic acid on wine after a year and its effect on taste. However, tannic acid is not a panacea for improving taste. I emphasize again that the good taste comes from the vineyards and ripe berries. I have always been working to improve the middle taste of wine, because the taste of expensive and cheap wine is very different.
Ray: This is a very delicate thing. Just like adding some new oak blocks to a neutral barrel that is less flavorful. People like to add the wine that is aged in oak, because it can make the taste of the product more delicate, but the key is to master the size and prevent it from being too far behind.
Aude: Cold soaking was first used in the brewing of Pinot Noir wines. People came to Burgundy and saw the temperature of the wine cellar was very low. They tried to use the same winemaking process in warmer producing areas like California. If you have time, pick the best berries, pick them in the cool morning, put them in a cold cellar and ferment with local native yeast.
Regardless of cold immersion or not, how will you manage once fermentation begins?
Ray: I think we have to find our own style.
LaurelGlen has been using open fermenters. The advantage is that it can blow off alcohol. I like the feeling of using an open fermenter, you can see and smell what is going on. You can also read the temperature from the wine cap. This is our style.
Over the years, we have improved the fermentation process. Because we are using the mountain solution, there is always a problem with tannins. Researchers who developed micro-oxygen technology found that the earlier the oxidation, the better the tannin. We have considered it carefully, and it turns out that it is really useful.
Therefore, when we brew, we use the crushing method (a red wine fermentation method, fermenting in this way, first using gravity to juice, let the grape juice flow into a large bucket, and then pumping the grape juice back to a large box Fermentation process) Allows the berries to moderately oxidize. When the juice is squeezed out and pumped back to the top, the combination of the wine cap and the juice is more tight than the typical fermentation, and the middle is also cooled. During this time, air is especially important for fermentation, especially with local yeast fermentation. As the fermentation returns, we can remove the seeds and dried peels during the “press-recovery†brewing process. Pressing at the end of the fermentation reduces the solids by 20%. The entire winemaking process helps to eliminate the over-extraction and bitterness we are most worried about.
Odd: I am making wine now, still using the cycle rotation, the wine cap and the delestage. These are mostly logistics jobs. Our venue was too small, so the work could only be done in a large box and had to press the hat. Some of my clients only require Pinot Gris for caps, while others require loop rotation.
In the above test, especially when using a centrifuge, the Pinot Noir will be fermented by cyclic rotation, resulting in a rough taste. When a large-diameter pump is used, since the grinding of the seeds is avoided, there is no rough mouthfeel. In our experiments, the above method is particularly beneficial for Pinot Noir: we can extract wines that are deeper and more full-bodied.
Barry: I have worked in many wineries, and I have tried all of them. But be flexible in practice. My experience is that there is no difference between a delestage process and a wine that has not been treated this way. The wines that are circulated and rotated are not much different from the wines that are pressed for recycling.
Ray: It is really useful to do that. If the effect of the press recovery method is to soften the tannins, then it is only counterproductive to treat the grapes in the lotis area, because the berries in the loti area contain insufficient tannins to soften. When using mountain berry winemaking, it is best to inject air into the pulp at the beginning to do oxidation treatment.
Barry: We are not talking about the role of air. In my experience, whether or not the wine cap is sunk is different from whether or not the wine is on the wine cap, but the difference is not big. If you prefer, some custom crushers will air pulse the wine caps and they will circulate and rinse as you wish. I am worried about time, no one wants to work in the middle of the night. If the cycle is carried out, it will be done at 6 in the morning and again at 8 in the evening, but the main fermentation will be carried out between 8 pm and 4 am; so this is a series of priorities.