How Long to Keep Sorbate?

updated 07/27/2024

What is sorbate?

Potassium sorbate is used in conjunction with potassium metabisulfite (K-meta) to “stabilize” wine, to prevent a renewed fermentation after backsweetening a wine. In laymen’s terms, sorbate + K-meta act as birth control for yeast, preventing it from reproducing, which prevents the yeast from producing a renewed fermentation.

This is necessary when a wine is backsweetened, e.g., additional sugar is added to sweeten a wine and to not restart the fermentation. If live yeast is present, it will start eating again. When yeast eats, it emits alcohol and CO2.

The CO2 may produce sufficient pressure to blow the cork out of the bottle. This produces a mess, and it results in a dry wine.

Although there are other methods of preventing a renewed fermentation, this post concerns sorbate.

Warning!

A renewed fermentation in the bottle can push out corks or possibly explode a sealed bottle. See this post for my thoughts on the subject.

The Problem

Sorbate, like many chemicals, has a limited shelf life. If stored in ideal conditions, it’s good for 2 to 3 years, according to some vendors. For sorbate, ideal conditions require a sealed container that protects it from air and light, and storage is around 70 F in a low humidity environment.

However, the typical home winemaker purchases a small package that is a plastic ziplock bag — which is as far from “ideal conditions” as one can get. This gets tossed into a drawer and is forgotten until needed.

The problem is that old sorbate has lessened effectiveness, and if the effectiveness is too low, any surviving yeast reproduces and blows the corks.

Using more sorbate if it’s old is not a good idea, as too much sorbate produces off aromas and flavors. Overall, the cost of replacing old sorbate is less than the cost of producing and bottling the wine.

My Solution

The short answer is buy as small a packet of sorbate as makes sense. Date the package, and 12 to 15 months later, bin it. Then buy new the next time it’s needed.

I’ve been told this is wasteful, throwing out a potentially useful additive.

I beg to differ. Let’s do the math. Locally, a 1 oz package of sorbate is $2.40 USD.

Thirty mid-grade corks are at least $6.00 USD, not including the mess produced by corks popping in the rack. And the loss of good wine. The cost of the ingredients are higher, plus the loss of time and effort.

A common saying when I was a kid was “penny-wise and dollar-foolish”. When making a decision, consider the wider picture and the overall costs.

Why 12 to 15 Months?

Anyone who’s read through my posts may have read that “why?” is The Most Important Question in Winemaking. If you haven’t, read it now.

Understanding “why” a recommendation is made is far more important than the recommendation itself.

Why?

[yeah, that’s a self-referential pun]

Various manufacturers have stated that 2 to 3 years in the shelf life for sorbate in ideal situations.

Let’s assume the package (typically a clear ziplock bag) has spent some months in a warehouse, and some months in the Local Home Brew Store (LHBS) before being purchased. The home winemaker has no idea what the actual age of the additive is. So assume the worst.

Assume that the package may be one to two years old when purchased, so I give it 12 to 15 months, then buy new when I need it.

Am I dumping a potentially useful product? Maybe. There’s no way to know other than to try it, and if it fails, but the cost of failure is a lot more than the cost of a new package of sorbate, so I buy new.