MLF question

You can get a paper chromotopography kit fairly inexpensivelly and tell that way.

I'd say from your description that ML is about finished. You're probably right that it started spontaneously too.

At this point you should rack the wine to get it off the lees and give it a bit of air, but there's no hurry to cold stabilize. In fact, since it's a red you needn't even bother with that. Just rack, sulfite, top up and bung tight. If you're using a glass container, leave an inch or so of headspace to prevent blowing the bottom out of the carboy.

Tom S

Thanks for the advise Tom and Paul! I am in the north east and typically the red grapes have lower ph and higher TA. So I have made MLF and cold stabilizing part of my wine making routine. I also find that cold stabilizng helps clarify the wine. I guess as with everything else there is probably some negatives to cold stabilizing?

Joe

Tom,

I've used airlocks on my carboys for years with no ill effects. I would recommend he use them at least until after next summer to avoid carboy blowout. I have carboys that have had airlock on them for 4 years.

Bob

Hi Pino,

I would not assume that the MLF is finished until you don't see any more bubbles at all, even teeny-tiny ones when you look really close at the neck of the carboy. So, I recommend just being patient and waiting it out.

If you're cold stabilizing to reduce acidity, note that cold stabilization isn't really very effective for that (0.05 TA reduction is about all). The only other reason I'm aware of to cold stabilize is to avoid tartaric acids from precipitating out in the bottle to form crystals on the bottom, which doesn't affect the wine really. From my perspective, the effort of cold stabilization isn't worth the results. Lugging 5 gallons carboys up from the basement on a cold winters day, along with the possibility of slipping on the ice and dropping the carboy, just isn't my idea of fun. But, maybe you're working in an area where all you have to do is open the barn/garage door.

I've never worked up the courage to try a chromotography kit ... my impression from sources I'd read was that using the kits required some skill and practice.

I know the question of when to innoculate for the MLF raises some debates. I always innoculate just before pitching the yeast, to give the ML bacteria time to take off before alcohol levels start to rise. The ML bacteria really like the skins, too, so I think there's an advantage to introducing them during the primary.

Jon [Check out my winemaking homepage

Just as a side note; you may want to check your pH and TA after ML. I made a bad assumption when initially making wine from grapes here in the Mid Atlantic. I thought that there would be plenty of acidity remaining after ML. (I did not check) After ML the wines I made in the past were HIGH in pH and did not keep very well. Apparently, the grapes were high in Malic and after that was converted the wines were high in pH. They were better at bottling time then after a year or two in bottle. Now, I add tartaric prior to or during primary fermentation and the wines are a LOT better.

Jon Gilliam wrote "If you're cold stabilizing to reduce acidity, note that cold stabilization isn't really very effective for that (0.05 TA reduction is about all)."

I disagree and I guess it depends on what type grapes you are working with. I grow vinifera and hybrids here in the Kansas City area. The red hybrids are high enough in acid that if you don't take steps to reduce TA you won't end up with a pleasant tasting wine. A couple of examples from this fall's grapes.

Baco Noir/Chambourcin blend. Time zero acid 0.94%. After ML 0.77%. After two weeks cold stabilization at 32F, 0.69%TA. Cold stabilization reduced acid by 10.4% from the post ML acid level ...well worth the effort.

Baco Noir/NY73 blend. Time zero acid 0.92%. After ML 0.78%. After two weeks cold stabilization at 32F, 0.71%. Cold stabilization reduced acid by

9.0% from the post ML acid level.

Both of these wines, properly oaked and aged will be very nice tasting red wines but without both of the acid reducing steps they would be far too acidic.

"I've never worked up the courage to try a chromotography kit ... my impression from sources I'd read was that using the kits required some skill and practice."

ML kits are very easy to use and take the guess work out of ML fermentations. PIWINE has an easy-to-use kit with clear directions.

Bill Frazier Olathe, Kansas USA

I certainly don't question the results you have obtained, but although you've been able to obtain a 0.08% TA decrease with cold stabilzation, I still feel that's a lot of work (for me, where I make wine in my basement with some steep stairs) for a fairly modest decrease. A number of fairly respected sources agree with me as well:

Jackish's "Modern Winemaking": "Chilling requires no chemicals but reduces acidity only in wines with appreciable tartaric acid and potassium. The reduction is generally small (often no more than 0.05%), requires controlled low temperatures, takes some time, and is difficult to monitor."

Jon Iversons's "Home Winemaking": "Super cilling a finished wine down to

20-30F for an extended period of time will cause some of the potassium bitartrate to precipitate. But unless the grapes had an abnormal level of tartrate salts to begin with, it will reduce overall acidity only slightly, perphaps 0.05%."

You can often get up to a 0.20% TA reduction with the MLF, so for me if that won't get me into the range I'm looking for, I break out the potassium bicarbonate (and prior to the MLF, since the MLF itself is inhibitied by high acid levels). So, I stand with my original statement, that cold stabilization is a relatively inefficient method of acid reduction (as a matter of fact I can't think of another widely used acid reduction method that is less efficient), and (of course depending on your winemaking location) can be a lot of effort.

Also, if you're going to seed your wine with cream of tartar during the cold stabilization to speed up the tartrate crystal formation, you run the danger of increased oxidation, since the cream of tartar needs to be well mixed into the wine, and the wine is more susceptible to oxidation when cold.

Thanks for the encouragement to try out a chromotography kit! Maybe I'll give it a go next year.

Jon [Check out my winemaking homepage

You have to remember though that the observations from the 2 references you cite are most likely based on their experiences with the grapes they worked with, my guess would be California vinifera. Bill's grapes are very different.

Also, if the number is stated in g/L as 0.5g/L instead of 0.05%, it's not that insignificant. In terms of the amount of tartaric acid in the wine, that's actually a reduction of 5-10%, and that can make a big diference in the taste. Plus you know where your acid really is before you bottle and avoid the reduction happening in the bottle.

Pp

J> > I disagree and I guess it depends on what type grapes you are working

My experiences are from Pennsylvania, working with likely very similar grape varieties : Chambourcin, De Chanauc, Foch, Cabernet Franc, Florental. And I still can't agree that cold stabilization is a significant acid decrease, at least in my winemaking setup, to justify the effort and risk. If I made wine in a garage or barn, where I could just open the door, I might plan for that 0.05% TA decrease I could get from cold stabilization.

But, I like to plan on my acid reduction plan earlier. If I've got a TA above 0.90, I'm going to plan on doing an acid reduction with potassium bicarbonate to get down to around 0.85 TA, from where I hope the MLF will get me right into the range I'm looking for.

Desired acidity ranges for dry red wines are 0.65 - 0.75, a whole 0.10 % TA range. So any adjustment you can make with cold stabilization is going to be less than even the accepted variation in desired TA in dry red wines, while a MLF or acceptable leves of reduction with potassium bicarbonate can lower TA by up to 0.20%, twice that variation.

So, I don't agree that the 0.05% acid reduction will make a big difference in the taste. Instead, it will make a difference in the taste less than half the normal variation in acidity within dry red wines, which for me does not qualify as big. You might instead be trying to say that you like your wine spot-on with respect to acidity, and I respect that, but there are easier ways to get this modest decrease in acid reduction without unduly affecting the wine (again, from my own taste buds, and yours may vary).

I do agree with that cold stabilization allows you to be more accurate about the acidity your wine will end up with after being in the bottle a while. But, even there it's not so accurate. I can't control the weather, so if I'm cold stabilizing by moving my carboy outside, temperatures may be such that I don't get complete tartrate precipitation, so there may still be some sediment thrown in the bottle.

I don't want to throw cold water, so to speak, on your cold stabilization --- I'm happy you enjoy doing it, and glad you get an acid reduction out of it that you feel is important in your wines. However, the two 5-gallon batch attempts that I made a cold stabilization, while they did realize some modest acid reduction (0.04 for the Chambourcin and 0.05 for the De Chanauc), just didn't seem worth the effort, especially when I ended up needing to complete the acid reduction with potassium bicarbonate anyways.

Jon [Check out my winemaking homepage

Interesting viewpoints on cold stabilization! I didn't actually hear any real negative aspects of cold stabilization other than the work required and risks on those super cold nights. I was afraid that it might strip some of the character from red wine?

Potassium bitartrate is pretty tasteless stuff, so removing the excess of it from wine doesn't really affect the flavor. It's mostly a cosmetic issue in white wines.

Tom S