Bottling a sweet wine:    POTASSIUM SORBATE

 

My wine has "fallen bright" and hasn't bubbled in a long time. 
It taste slightly sweet, can I bottle it now? 

Potassium Sorbate greatly inhibits yeast and is used as a preservative for sweet wine.

Test the sugar level, using a -5 to +5 hydrometer.If the reading is below a (negative) -1.5 degrees or -2 degrees brix, then the wine is dry and safe to bottle without sorbate. If the hydrometer reading is higher than a -1.5, such as a 0 reading or a plus 1 degree, then there is residual sugar. 

Add sugar to sweeten to taste after you have sorbated the wine and it is stable.

If you add sugar to sweeten to taste, use cane sugar instead of corn sugar.  Calorie for calorie there is twice the taste of sweetness with cane sugar.  Red or white wine with residual sugar should be treated with sorbate prior to bottling.

Your wine should be brilliant, having fallen bright.  Test the SO₂ level of the stuck wine with a Titret SO₂ test kit. It should be above 40 (to 80) ppm.  If needed, dose the metabisulfite to at least 80 ppm at about the same time you do the sorbate, but prior to.  If you have not been using Potassium Metabilsite during the winemaking process, you may not NOT be able to achieve the proper meta levels by adding it at this time.  Re-run a titret test.   Adjust the meta if needed.

If you do not have proper K Metabisulfite levels at this time and any malolactic bacteria are present, it will consume the Sorbate.The result is an off taste and an odor of geraniums for which there is no fix. 

ADD SORBATE, at the rate of 1-2 grams per gallon: 1/2 teaspoon is approximately 1 gram.The density of sorbate is different from one supplier to the next.  If you do not have a gram scale, you should probably dose at the higher rate of 2 grams per gallon, which would be approximately 1 teaspoon per gallon.

Now, you can cold stabilize. Put glycerin or sufficient alcohol (vodka) in the airlock to prevent freezing. Place the carboy at 20-25^o F for 2 weeks or more. Excess tartrates will precipitate from the wine. This mellows the wine by reducing the acid. It will help stabilize the wine by preventing these tartrates from settling out after bottling. Rack into a clean carboy while cold, adding proper metabisulfite. Top up with wine. If you don't have time to rack while still cold, it is ok. The crystallization of the tartaric acid will not reverse instantly, but it will slowly.

If you add SORBATE without cold stabilizing, allow 24 hours before bottling. However, the addition of any potassium ion will make the wine unstable and this is why cold stabilization is recommended after adding sorbate. 

If you do not want to use sorbate and have a sweet wine to bottle, use pressure safe bottles such as champagne or beer bottles. The residual sugar should be 2% or a difference of 1.000 on the +5-5 hydrometer.

Filter if desired and bottle when stable.  Always rinse bottles with B or C Brite or a meta solution.