I am a newbie to wine making. I understand the primary fermentation temp should be 65-75? How about the secondary fermentation and subsequent processes? I am wanting to make my wine in my basement but it might be too cool. Thanks. Todd ----- Hello Todd, This is a great question. The answer to it is quite often what trips up many beginning home winemakers. The effect that temperature has on a wine fermentation is enormous and greatly underestimated by many. This is particularly true for those new to wine making. As an example to the enormity of its effect, consider the 65°F. you mentioned above. This might allow a wine fermentation that is barely noticeable to occur, whereas the 75°F. you mentioned might end up producing a fermentation that results in a spewing volcano of foam. That's how dynamic temperature can be to a wine fermentation. The type of wine yeast you use, along with the wine you are fermenting and a whole host of other, more minor, variables also factor into how dramatic this comparison plays out, but without a doubt fermentation temperature is always vital enough to make your question an important one. Whether or not your wine must is in a primary fermenter or secondary fermenter is not what matters to the temperature you maintain. What does matter are the readings you are getting with your wine hydrometer. You will eventually want to keep your wine at a little cooler temperature than what you previously mentioned, but you also want the fermentation to be complete before moving the wine to these cooler temperatures. You determine if a fermentation is done by taking a hydrometer reading, not by whether or not it is in a primary or secondary fermenter. Sometimes the fermentation finishes while it is still in the primary fermenter. Sometimes the fermentation carries on for a great deal of time while it is in the secondary fermenter. The reason for this inconsistency is because of all the variables mentioned before: yeast strain, type of wine, etc. You can read more about checking the fermentation with a hydrometer in the article, Getting To Know Your Hydrometer, listed on our website. You may also want to check out, How To Know If Your Fermentation Is Done. Even though you suggested wine fermentation temperatures between 65°F. and 75°F., we recommend between 70°F. and 75°F. Once you get below 70°F. some wine yeast strains have a tendency of dragging out the fermentation. Once the fermentation has completed, and this has been verified with a wine hydrometer, you can maintain a lower temperature. An optimal temperature for storage would be 55°F., but it is not extremely critical. Just do the best you can to keep it out of warm temperatures once the fermentation has completed. What's more important is that the temperature be even and not be all over the place while the wine is in storage. Thank you for your great question on wine fermentation temperature. Just remember that you should have some type of control of the temperature. You do not want the fermentation to be too low or too high, but just right. I hope this information helps you out. Best Wishes, Ed Kraus ----- 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.