Bentonite

Hello, I use bentonite to clear a wine as a last resort, which hasn't been all that many times. I will leave others to talk about their experiences and whether they feel the taste of the wine is affected. Most of the time, my wines clear of their own accord by letting them sit long enough, racking them another time, or cold stabilization. It all depends, I guess, on what expectations you have about your wine and what it looks like. Others have heard this story - my expectations of my wine is that it be clear with a dusting of sediment (if at all) in my bottles. My brother sent me some of his wine - it tasted fine. But, the wine was cloudy and there was about a

1/2 inch of sediment in the bottom of his bottle. It didn't bother him, but I wouldn't send a gift of wine which looked like that.... It all depends. Darlene ;o)

I've never seen a quantitative value placed on the flavor stripping capacity of bentonite. Perhaps others could comment on this. Though it seems reasonable that this would be proportional to the concentration at which it is used.

Usually, the primary goal of fining wine is to improve taste with the added benefit that it can improve clarity as well. As a rule, I do not fine my red wines. I find that time is the best fining agent. After a year or so red wines are usually very clear - especially if it's had time in oak casks. For whites, I often do a light bentonite fining after primary fermentation has ceased. As I have been reminded by folks on this newsgroup, let your taste be your guide.....and have patience.

RD

Drunken Observer wrote:

I've never seen a quantitative value placed on the flavor stripping capacity of bentonite. Perhaps others could comment on this. Though it seems reasonable that this would be proportional to the concentration at which it is used.

Usually, the primary goal of fining wine is to improve taste with the added benefit that it can improve clarity as well. As a rule, I do not fine my red wines. I find that time is the best fining agent. After a year or so red wines are usually very clear - especially if it's had time in oak casks. For whites, I often do a light bentonite fining after primary fermentation has ceased. As I have been reminded by folks on this newsgroup, let your taste be your guide.....and have patience.

RD

Drunken Observer wrote:

I tend to avoid bentonite period, unless kits provide it. Usually in those cases, bentonite is added to the must at fermentation time. I assume this holds it together and keeps the vigor from going overboard. I've avoided using bentonite with kits at fermentation and sure enough the foam was excessive.

When I ferment from fresh grapes I prefer to use nothing and let it settle ut over time, and racking.

If you can get away from using any fining agent at all, and allow solids to settle out naturally over time, then rack off sediment, that is your best bet. Your bottled wine will still throw sediment over time, but you will notice an improvement in body, and flavor.

If you prefer not to wait for natural clarification, you have no choice but to filter or use something to fine. Or deal with heavier sediment in the bottle.

Regards Jeff

D.O.

Bentonite is primary used to remove excess protein from white and blush wines made from grapes. Grapes contain small quantities of protein, and the protein is carried over from the grapes into the wine during fermentation. Originally, the protein molecules are much too small to be visible in the wine. However, under certain conditions protein molecules link together (polymerize) and grow larger. After many protein molecules have linked together, the protein particles are large enough to be visible, and the particles are too large to remain suspended in the wine. This growth process is very slow at normal cellar temperatures, but when wine becomes warm, the protein molecules grow more rapidly. At temperatures of about 120 degrees, protein molecules can link together and form large particles in a short time.

Winemakers call protein hazes "hot instability" because warm storage conditions trigger the phenomena. Leaving a bottle of Sauvignon Blanc in a car trunk on a hot summer day can produce a graphic demonstration of hot instability. When white or blush wines are subjected to warm storage conditions, protein hazes can form quickly, so all commercial white and blush wines are specifically treated to remove the excess protein before bottling.

Excess protein seldom causes stability problems in red wine. Red wines contain phenolic compounds that react with the protein during primary fermentation, and the excess protein precipitates out of the wine. White and blush wines contain very little phenolic materials, so the winemaker must use a special treatment to remove the excess protein from these wines.

Bentonite is a very fine, clay-like material. It has a negative electrical charge, and it is commonly used by commercial wineries to remove excess protein from both white and blush wines. Occasionally, it is used for clarification fining of white and blush wines, and sometimes bentonite is effective in clearing hazy fruit wines. It is often used at dose levels ranging from 0.5 to 4 grams per gallon, but a normal dose is 1 to 2 grams of dry bentonite per gallon of wine. Bentonite can strip desirable aromas from wine when used in excessive amounts (more than 2 grams per gallon), so bench testing should _always_ be done.

Bentonite should be mixed with water and allowed to stand for twenty-four hours before being adding to the wine. Bentonite can be mixed easily in a blender. Put the required amount of hot water in the blender, turn the blender on, and slowly add the dry powder. When the mixture is cool, place it in a refrigerator and allow the bentonite mixture to hydrate for at least

24 hours. Add the hydrated mixture to the wine slowly and stir continuously.

Lum Del Mar, California, USA

Drunken Observer wrote >"I would like your comments on the use of bentonite. I read somewhere that it can grab as much as 1/5 of the flavor. Should we use it at all? At what stage should we use it? Any other opinions on other fining agents? I don't sell my wine and don't mind not crystal clear if I can get a better tasting product."

DO - For white wines I treat with bentonite when fermentation is complete. When very young some of these wines have a harshness. The bentonite fining seems to help smooth the flavor of these wines. I follow bentonite with cold stabilization at near freezing temperatures. This helps compact the sediment from the bentonite fining. After racking I treat with PVPP (Polyclar). I believe this helps keep white wines light in color. Both of these fining treatments yield a better looking and better tasting finished wine IMO.

Bill Frazier Olathe, Kansas USA

Thanks for the clear and enligthening info!

:-)