Best way to stop fermentation for a sweet wine


I have a white Zinfandel that's at about 1.050 and I'd like to stop it there for a sweeter wine. I've read about a few ways to stop it but wonder what's the best. I have potassium sorbate, potassium metabisulfphite, I have a filter, and its about 32f outside right now. I could stop the fermentation by putting it in the cold for a while and then add the sorbate and metabisulphite and then filter? I'd like to use as little chemicals as possible. Thanks guys.
Reply to
Dirty Harry

If you stop it now, will there be enough alcohol in the wine for you? In other words, what was the starting sg?
BTW, most people ferment to dry to get 'full' alcohol & then backsweeten. Your suggested approach MIGHT work, but I have never tried it.
Steve
Reply to
Steve

Dirty Harry:
Depending on how big your container is, it could take a long time to get down to 32 =B0F, so that's a consideration. Regarding your desire to use as little chemical as possible, there is a usual dosage of sorbate that most people use, but I found an article that gives a table of the dosage needed based on alcohol %. Obviously, the higher the alcohol%, the lower amount of sorbate needed. Here is the link:
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10%: 200 mg/l 11%: 170 mg/l 12%: 135 mg/l 13%: 100 mg/l 14%: 70 mg/l
The above numbers are assuming that the levels of SO2 and pH are correct (whatever that means). The threshold for detecting the geraniol smell is 182 mg/l. Another source that I found is Margalit, who says to use at least 200 PPM of sorbate, and then points out that the smell threshold is 150 PPM.
In your case, since you are at 1.05, and assuming that you started at 1=2E09, then you would have a pretty low alcohol content, which would mean that you're gonna have to use a lot of sulfite and sorbate.
Reply to
Franco

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Just some clarifications - geraniol smell only develops if a sorbated wine goes through a malolactic fermentation, that should not be an issue if the wine is properly sulfited. As I recall the article with the table, one major assumption was that the yeast population is low, and that's not the case for an active fermentation.
For the past 2 years, I've been making off-dry and sweet wines using this method and as Steve pointed out, it's way harder than fermenting to dryness and then back-sweetening. The method I've been using is to use the cold outside temperatures to stop the active ferment, wait until most of the yeast drops down, then rack and sulfite and fine at the same time with bentonite and Sparkalloid, keeping the wine as cool as possible all the time. Finally, I filter and add the preservative - sorbate last year and benzoate this year. After all this, I'm finding that when I bring the wine back to room temperature, there is still some yeast activity. Last year I dealt with it by re-filtering but the wine is lacking in aroma, so I'll probably just add some sorbate this year again - so after all the trouble, I'm basically at square one. I think I'll go back to back-sweetening next year.
Lastly, 1.050 seems awfully high for a white Zinfandel, that's more residual sugar than most dessert wines have! Your alcohol levels will be low and because of that the wine will be in more danger of spoilage. If you really want it that sweet, I'd highly recommend fermenting to get at least 10-12% of alcohol and then adding sugar or sugar syrup.
Pp
Reply to
pp

Thanks for the link! Sorry the SG is 1.005, my bad. It's almost down to 1 but its still fizzing pretty good. I'm thinking that stopping it sooner will leave some of the flavour of the original juice and give me a fruiter Zin instead of fermenting all the sugar out and then sweetening after (I just finished one this way so I'll be able to compare later on.) I'm told that a #1 filter is small enough to get out the yeast cells so what about doing a #2 then a #1 and then adding the sorbates and sulphites at the end to make sure it doesn't start back up? Gonna get some filters today and give it a whirl I think. Thanks!
Reply to
Dirty Harry

"Just some clarifications - geraniol smell only develops if a sorbated wine goes through a malolactic fermentation, that should not be an issue if the wine is properly sulfited. As I recall the article with the table, one major assumption was that the yeast population is low, and that's not the case for an active fermentation.
For the past 2 years, I've been making off-dry and sweet wines using this method and as Steve pointed out, it's way harder than fermenting to dryness and then back-sweetening. The method I've been using is to use the cold outside temperatures to stop the active ferment, wait until most of the yeast drops down, then rack and sulfite and fine at the same time with bentonite and Sparkalloid, keeping the wine as cool as possible all the time. Finally, I filter and add the preservative - sorbate last year and benzoate this year. After all this, I'm finding that when I bring the wine back to room temperature, there is still some yeast activity. Last year I dealt with it by re-filtering but the wine is lacking in aroma, so I'll probably just add some sorbate this year again - so after all the trouble, I'm basically at square one. I think I'll go back to back-sweetening next year.
Lastly, 1.050 seems awfully high for a white Zinfandel, that's more residual sugar than most dessert wines have! Your alcohol levels will be low and because of that the wine will be in more danger of spoilage. If you really want it that sweet, I'd highly recommend fermenting to get at least 10-12% of alcohol and then adding sugar or sugar syrup.
Pp"
Thanks good to hear from someone who's tried this. Yea My SG is 1.005 sorry for the mixup. I tasted some when racking yesterday and really liked the level of sweetness. What size of filter are you using? I've read that I have to use a #2 and then a #1 (.5 microns?) so it doesn't plug up but like you said I think it could strip out too much flavor.
Reply to
Dirty Harry

Are you sure you want to stop at 1.050? That is very sweet and very low alcohol.
If you don't want to use chemicals chilling and keeping the wine cold are an option. I am not to thrilled with sorbate. If you use it add sulfite too.
I am thinking of trying hot bottling or thermotic bottling of my next sweet wine. One, you take the wine to 122 F and bottle it warm; put it in the boxes warm and let it cool slowly. The idea is yeast and bacteria are killed by the longer exposure time. The other method is to take the wine to 154F for a few seconds and cool it rapidly and bottle. You could do that with some stainless tubing and a pot of hot water and another exchanger and a pot of ice water. I have too much else going on right now to try either, but can let you know down the road...
Joe
Reply to
Joe Sallustio

One last thing, will the potassium and sorbates dissolve completely clear? I want to add a little after its filtered if I can. Thanks
Reply to
Dirty Harry

Absolutely. Put them in seperately and don't add them dry; either add a bit of water or pull off some wine to mix them in. 1.005 is off dry and sound like a good level; you need to get it cold now because it does not stop immediately.
Joe
Reply to
Joe Sallustio

The .5 micron filtrer is #3 - assuming you're talking Mini/Super jet? They label is as "sterile" but it isn't actually, so even going through #3 might not be enough, #2 certainly isn't. Last year I did #2 first and then 2 passes through #3; this year I'm doing only #2 because of the stripped aroma last year.
Also, make sure you degas the wine before filtering, otherwise it will happen pretty violently during filtering - I actually suspect this more than anything for the aroma stripping last year.
One other thing - what yeast did you use? Some are easier to stop this way than others - one that's _supposed_ to be temperature sensitive is Cotes de Blanc. I've used it on two wines this year and it's just about impossible to kill!
Probably the best setup for doing it this way is a temperature controlled old chest freezer, if I had space that's what I'd use.
Pp
Reply to
pp

If you're talking filters for the Mini Jet or Super Jet , then #1 is COARSE. It will not remove all of the yeast. Even the #3, labelled Sterile, is not fine enough to remove all the yeast.
Steve
Reply to
Steve

There are no safe chemicals that will stop an active ferment. And I do use chemicals including Sorbate and K-meta. They are great for preventing a ferment from restarting but will not stop one at doses that you could not taste. The cheapest way is to put it in a cold place (down in the low 40's or 30's) to make the yeast go dormant. Keep it there while it clears. Then rack it off the yeast and treat with sorbate and K-meta. But you should keep it cold untill it clears.
Ray
Reply to
Ray Calvert

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