The procedure outlined here is applicable to almost all kind of fruits with the exception of citrus and citric acid containing fruits. Why? The organic acid called citric encourages acidification resulting to a sour tasting wine. Also, addition of citric acid to adjust acidity is discouraged. Use tartaric acid instead.
Trivia: The term “wine” originally means alcoholic beverage made by fermenting mass of grapes and grapes only.
1) Juice Preparation
Wash fully ripe fruits, cut and scoop out the flesh. Add 3 liters water every kg juice. Add sugar to adjust to 20ºBrix for dry wine and 25ºBrix for sweet wine. I am not giving a certain ratio as sugar concentration changes with different fruit batches. The right thing to do is get the initial brix first (using sugar refractometer) then add sugar gradually (with mixing, of course) until the target is reached. Math savvy can compute how much sugar is needed right away. However, gradual sugar addition is still recommended.
Add 5 ml of 10% sodium metabisulfite per gallon juice to destroy spoilage microorganisms. Cover the jar and let stand for 16-18 hours at room temperature. Note: sodium metabisulfite is processing aid, will never be a part of final product. It is expelled out by the fermentation process.
You may use campden tablet instead of sodium metabisulfite. They are practically the same but the first is easier to acquire.
2) Starter Preparation
Gather 10% of the total volume of juice and pasteurize (heat until 90ºC). Cool to 40-45ºC or until it can be touch comfortably by hand. Inoculate with pure culture of wine yeast. Let stand for 18-24 hours and inoculate into prepared juice.
Traditional bubod can be used as culture. Bread yeast as well. They are not made for the purpose though and you may end up dumping your product. Getting high quality wine cultures in sachets is the best. If your a biology geek, another option is getting pure cultures in agar slants and growing it on your own little lab.
Only 10% of the total prepared solution should be pasteurized. The remaining 90% should be not. The unwanted microorganisms in it are chemically killed with the use of metabisulfite. Heat is avoided to preserved fruit natural flavors.
Add starter culture – the liquid we prepared in “Starter Preparation”. Cover the container with cotton plug and ferment for two days. Replace the cover with fermentation lock and continue fermentation for 3 to 4 weeks. Fermentation is done when bubbling stops.
Fermentation lock is like a one-way door. It allows escape of carbon dioxide (produced by fermentation), but prevents air entry. It can be simply made by boring a hole on container cap. Fitting a flexible hose in cap hole. And dipping the other end of hose in small jar half-filled with water. You’ll see bubbles in this when fermentation is active.
4) Aging and Clarification
Freshly harvested wine is ready for consumption but storing for at least one year improves its clarity and flavor. After aging, siphon the clear wine, taking care to avoid the settled solids at the bottom. Pack into tightly sealed wine bottle.
Temperature affects flavor outcomes. Play with room temp (25ºC) for the start. Make it higher or lower for the next trials until you get the desired outcome. Every yeast has its optimum temperature range. Please refer to its profile!
How can we control room temperature? Install a warmer or air conditioning unit.
Juice pH is also a critical factor in wine waking. It is not mentioned in “Juice Preparation” but its adjustment should be done. It affects flavor profile. The process may fail completely when pH is too low. Anything above 3 should be fine but below is disaster. Yeast cannot thrive below that.
Mixture pH can be measured using pH meter. Maybe lowered with the addition of tartaric acid. Again, don’t use citric. Add potassium bicarbonate to raise it. It may also be adjusted by blending juices of different pH, which is only feasible if you have a lot of fruits to play with.