Thanks for the great question and bringing up a great wine making subject. Freezing wine making fruit is a great tactic for the home winemaker. It’s one of the wine making tips I share with people quite often.
Just like you said, freezing the fruit breaks down the fiber that is holding it together. When it comes time to actually using the wine making fruit, just thaw it out and process as you normally would. You will find that the color and flavors will release from the fruit into the wine must more readily. This means you are getting more out of your wine making fruit.
Not only does freezing the wine making fruit have this subtle advantage, but there are a couple of more-obvious advantages as well. Freezing the fruit affords you the luxury of being able to make the wine when you are ready to make the wine. If the strawberries are ready, but your not… freeze ’em!
Another advantage is sometimes you don’t have enough fruit to make an entire batch of of a particular fruit wine recipe. Not all fruits come in evenly. The solution is to freeze the fruit as it comes in. Freezing the wine making fruit allows you to hoard until you do have enough to make a full batch of wine.
There’s really not much to know about freezing the fruit. Its okay to chop up your larger fruit. But for berries, you are better off leaving them whole. I strongly suggest sanitizing all wine making fruits in a bath of sodium metabisulfite and water solution before freezing. Drain the fruit thoroughly. Also, common sense would dictate that the “bad ones” be pick out and discarded.
If you plan on freezing the fruit for a longer period of time, say six months or more, you may want to consider packing the fruit in sugar syrup. This will help to eliminate any negative effects from freezer-burn. Just like it sounds, you use just enough sugar syrup to cover/submerge the fruit before freezing.
If you do decide to pack your fruits in sugar syrup you will want to add less sugar then your wine recipes calls for. This is to allow for the additional sugar that will be incorporated into the wine must along with the fruit.
A simple way of handling this adjustment is to rely on your wine hydrometer. Use the hydrometer to tell you how much sugar is needed in the recipe instead of adding the amount called for in the wine recipe. Just add sugar until the desired alcohol level is reached the the hydrometer’s potential alcohol scale.
Freezing wine making fruit is not a necessity to making wine. You can make incredible wines without freezing the fruit at all. Freezing fruit is just one more method you can use to help the fruit keep while waiting from more.
Ed Kraus is a 3rd generation home brewer/winemaker and has been an owner of E. C. Kraus since 1999. He has been helping individuals make better wine and beer for over 25 years.