Jack Keller states: "The surest method of controlling yeast variety is to pasteurize the must to 150 degrees F. to kill all indigenous yeast and bacteria, cool it to around 68 degrees F., and then inoculate it with the desired yeast. This is not as romantic as promoting spontaneous fermentation of the yeasts the grapes themselves bring to the press, but for the average person it sure is less risky. But pasteuriztion ruins the must of many potential winemaking ingredients and should not be practiced unless specified--or unless you are willing to risk the batch by experimenting."

With my fruit wines, we have been basically pasteurizing by pouring our boiling water/sugar (syrup) solution into the fruit. Upon cooling we pitch the proofed yeast. What winemaking ingredients are in the must that Jack Keller says could be ruined using this method? It seems to allow the must to start fermenting faster then when using the metabisulfite method. Are we wrong?

Andie Z

Andie -
You're probably OK. In general, you don't want to "cook" the
fruit or the wine before fermentation. Heat will drive off some of
the volatile flavor compounds, and with enough heat you'll start to
caramelize the sugars, which you probably don't want. However, some
amount of heat is probably just fine. Pouring boiling water or sugar
solution over the fruit shouldn't hurt much, if at all. Personally, I
never boil anything when making wine. But it's as much a matter of
laziness as anything. If you feel better about it by boiling the
sugar solution first, go right ahead. I don't think you need to, but
it shouldn't hurt the wine.

Doug