I'm making a sweet Orange Muscat from Brehm juice.
After starting the fermentation, I monitored the activity until the wine achieved the taste (and brix level) I desired. I then hit it with potassium metabisulfite, sorbate, and bentonite, and moved the wine to my ice-cold garage. The wine clarified beautifully. After a few weeks, I brought the wine back inside. To my horror, after about two weeks, a haze has developed.
What to do? Patience? Gelatin counter-fining? Any suggestions appreciated.
Lee - Did you rack off the sediment? Did you measure the sulfite content? Are there any slow, tiny bubbles rising? I ask because you may have a malo-lactic fermentation going on. I've had this happen in sulfited wine before in my cellar. The ML bugs are floating around with yeast in the cellar atmosphere and it's hard to prevent a spontaneous ML fermentation. If you have the ability you might do a chromatography test to check for lactic acid and check into Lysozyme...it can stop a ML in it's tracks.
Lee .. I doubt it's ML ....SO2 will stop ML "in it's tracks"! But, as Bill asked, did you check free SO2? ... and pH?
You might want to chill it back down in a hurry in case it's primary that has restarted ... or else go dry and add back some sugar. What exactly was your sorbate protocol?
Please note: .. SO2 "WILL NOT" arrest a primary fermentation!!! Cold temp will slow it down .... VERY cold temp will bring it to a virtual stop! But, you need to "separate" the yeast from the wine to yield a sweet product, or else "off it goes" after the temp comes back up. Nearly all wine yeast species are SO2 "tolerant" to a great degree! Sorbate is a "brute force" method of stabilization. Sorbate prevents yeast reproduction. You must use an external method (chilling) to separate the wine from the yeast, in order for sorbate to be very effective, and even if it does stabilize the wine's sweetness, it contributes an undesireable flavor.
Long story short - making sweet wine is a bitch! It's been said many times here .. for small batches, make it dry - add the sugar before serving!! Otherwise ... get a REAL sterile filter ($$$) and learn to use it!!!
As for SO2 amt ... 20 ppm free would give you 0.8ppm molecular at pH
3.2. At pH 3.6 you need 50ppm free to get the desired 0.8ppm molecular . However, even the low level of SO2 you have would arrest ML according to my experiece.
Believe me!! I "feel" your pain! I pronounce it "pinot gris" ... which, I believe is Italian for "Damn!! this stuff is fermenting again!!"
So .. 0.2 um will do the trick (0.45um will) .. if it IS 0.2um ... "absolute"! Remember, the key to sterile filtration is "confidence" in your pads and "sanitation"!!! It is no easy trick, IMHO!
But, I'm still puzzled. Did you re-chill the wine? Did it clear again? It must be "crystal clear" before you run it thru a sterile filter!
I don't use sorbate, so I don't know if you added enough to stun the yeast. You didn't say what your SO2 went up to after your last addition ... you have a high pH so you still might not have whacked the ML bugs with SO2. I guess we still don't know what started up when you raised the temp ... primary or MLF.
I would suspect primary if you see activity but you don't. That is a whole lot of sorbate, it's twice what I would use. Are you sure it was good? It only has a shelf life of about 1 year. I would not add it to an active ferment, it will not kill active yeast. The yeast must be removed first as stated previously.
I'm not sure that I like tight filtration. I really think it strips flavor, although others disagree. Everything must be sterile, corks, bottles and wine. That's hard to do. Why not rechill and rack gently while cold and see what happens. I'm experimenting with using honey as a sweetener, it's usually nutrient poor.
And Charlie, I always have issues with Pinot Gris too. It seems to be the wine I put the most effort into for the least benefit. I'm pretty sure it's a clone of Pinot Noir, which would explain a lot... :o)
I've got one of those Presque Isle 10" stainless cylindrical filters. The .2um filter I have is two-stage microfiberglass/polycarbonate job. I'm thinking it will do the trick.
No, have not rechilled it.
I added the sorbate to the primary fermentation. Like I said, that seemed to quiet things down significantly. I've not checked the SO2 levels since I made the addition on Sunday, but I expect the levels will be more acceptable. I'll check that tonight.
I also ran a chomotography to check for ML activity. There *might* be something going on in that regard, as there faint spots for both malic and lactic acids. I suppose I can hit it with some lysozyme, just to be sure. On the other hand, there appears to be *zero* activity that I can see - no bubbles, nothing.
I'm open to suggestions. Lysozyme addition? Coarse filtration followed by sterile filtration? Re-chilling? Gelatin? All of the above?
Wait,that's not good. You do NOT want MLF in the presence of sorbate, it's too late to go for MLF if you used sorbate in any amount. Your wine will smell like geraniums. Lysosome encourages MLF from what I read, not discourages it. I never use it so can't speak much to it's benefits.
You have no activity so that is good. I would suggest you use at least
0.8 molecular for the free sulfite value at pH 3.6, it's 50 PPM. I would chill and rack off the lees if it clears when cold, if it doesn't counterfine, gelatin is more effective with a little shot of tannin first as I recall, or you could use sparkleoid or isinglass.
Free SO2 is up around 100 now, a bit high, but not outrageously so. Have moved the carboys back out to the garage to catch a chill. We've got some temps in the teens coming, so I'll let it cool down for a few days, then rack it cold and see what happens.
Lee - If you have malic and lactic acid spots on your chromatography paper you have a ML fermentation in process. In some of my wines that have a MLF underway it's very difficult to see bubbles at first. The wines have just been cloudy like you mention. As the temperature warms up and/or after the bacteria have really increased in number ML fermentation is more apparent with lots of bubbling.
I read here that sulfite will stop or prevent MLF. This may be so if the sulfite is added before a MLF gets underway or if enough SO2 is added. However, I've had MLF take place in some of my wines that I believed were well protected with sulfite. Since I add ML culture to my red wines the organisms are just floating around in my cellar and it's real hard to prevent MLF in my white wines.
I had good success stopping MLF by adding Lysozyme at 200 to 500 ppm (at least 0.75 grams per gallon) in cloudy wines that show malic and lactic acid spots like you describe. The wines I've treated have become crystal clear in a couple of days.
Once you get the MLF stopped and the wine clears your 0.2 micron Duofine filter will render the wine sterile. But sterile operation is next to impossible in typical basement operations. Everything downstream from the filter has to be sterile...that's the big problem. But, proper SO2 levels, K sorbate at 200 ppm and sterile filtration should be enough.
Check out PIWC, Scottlab or The Winelab for some info on Lysozyme. Good luck.
Joe - I have Lysozyme that I bought in 2002. It still worked this winter to stop an unwanted MLF in this years Vidal. I store it tightly sealed at cellar temperatures between 60 and 70F. Bill Frazier Olathe, Kansas USA
I added 100ml of 5% lysozyme solution to each carboy today, which (if I calculated this correctly) should give 200ppm. I was *very* careful to stir gently so as not to disturb any of the lees. Cross your fingers. Except for the haze, its already a very tasty wine.
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