Chris Pearmund: Hi, I am Chris Pearmund here in Haymarket Virgina at the winery La Grange and we are taking about wine making for the commercial producer as well as the home wine maker and some of the the many things that are similar that could be useful for a home wine maker or to enjoy and appreciate as a hobbyist in the wine industry to enjoy a nice glass of wine. Today, in this segment we are going to talking about basically the middle time of wine in bulk and some of the bacterial issues and cleanliness issues and some of the things that happen from wine post-fermentation. Cleanliness is very important in a winery. Basically fruit is fermented to wine that wine still basically fruit juice. So you want keep away any oxygen from the wine and you want to keep way any bacteria that could spoil the wine and throw off flavors. Again there is no bacterial spoilage out there that will harm human being but there are a lot of things that can happen to the wine to make it taste not very nice.
One of the things we do in cleanliness is to keep everything clean before and after anything touches wine in all environment, in the air, on the ground, inside of a barrel or anywhere else. Also temperature is very important when making wine. In liquid when you have a temperature fluctuation, the liquid will expand and contract. If you have a bottle of wine or a barrel of wine, if there is any temperature fluctuation, that temperature is going to make the wine expand and contract and suck in oxygen. We would like to keep oxygen levels at zero during wine storage in bulk. It's very important. So wine barrels will have large bungs on them to keep away any oxygen and they are very tight.
One way to reduce oxygen pickup is to use what is commonly referred to as bubblers or airlocks. During fermentation a lot of gases are released or CO2 gases and the bubbling action will allow the gases to escape like a plumber's trap, but the air cannot get back into the liquid, the wine to spoil the wine. We want to keep oxygen levels at zero during fermentation and after fermentation. During fermentation these would be used, after fermentation a solid bung will be put on, to keep away any oxygen. Also again temperature is important, you want to keep this air space to absolute minimum. Naturally there would be some CO2 there rather than oxygen. So you wouldn't have any issues of oxygen pickup. Another way to keep -- reduction down in any bacteriological or biological activity is the use of Potassium Metabisulphintes often commonly known as Sulphur or Sulphites or SO2.
SO2 at a rate of 30-40 parts per million available in the wine will scavenge away any dissolved oxygen in the wine and in a completely anaerobic environment or oxygen-deprived environment, there will be much less risk of any biological activity. Therefore the wine is going to last a lot longer in storage and help the wine develop more complex flavors during the six months to up to a year before the wine actually gets bottled. One other transformation that does occur biologically often is called the Malolactic bacteria, you probably heard of it, Malolactic or ML Bacteria. Basically Malolactic bacteria conversion is when you have Malic Acid which is naturally available in grapes transformed into lactic acid. Malic Acid is the green apple tart crisp flavor of a tart white wine. A bacteria will eat this tart green Malic Acid and release Lactic Acid, the same acid as in milk and cream and butter that viscous, soft, buttery kind of texture. That will make Chardonnays more buttery more viscous and it will make red wines Bordeaux variety, those have less astringency to them and less sharpness and crispness to them, a kind of fat in the mouth.
So it's a bacteria we can add, this is also naturally in the air. Another important part of the wine aging process is the storage container you will be using. Whether you use use oak barrels or stainless steel or glass container they are all important for a few factors, to not allow very much or any oxygen in. If you have a glass this container or stainless steel container, they are completely impervious to oxygen except where the cork is and you want to very careful about eliminating any oxygen there. With the oak barrel there is some oxygen that will float through very slowly through the oak barrel. These container hold between 60-70 gallons of wine and the very small amount of oxygen will help allow the wine to mature slowly. If you have a large -- the larger the container, the less oxygen will be made available just the volume of size.
Many large commercial producers have large stainless steel tanks where they try to duplicate what the barrel aging does. They do that with two different factors, one is through Micro-oxygenation, which is where small oxygen emitter will be placed in the bottom of your large stainless steel tank allowing small measured units of oxygen to help mature a wine in a closed environment. Also it will be added with small amount oak chips or or oak tannin to kind of duplicate them with the flavor profile assimilated with oak barrels. Oak barrels are French oak or American oak or Hungarian oak, different species do have different flavor component. I don't really want to get into that at this time but basically to know that the oak barrel, there are two basic things, allow small amount of oxygen in for maturity and allow the small flavor development to accentuate the flavors to the wine and compliment those flavors. On the next clip we are going to talk about fining, filtration and pre-bottling preparation of your wine. Thank you.