Scrub ube well, then peel and chop them into 1" chunks.
Add ube to a large pot. Add 1 gallon of water, bring to a boil.
Once water is boiling, turn heat down and simmer for 1 hour.
While the pot is simmering, prepare your fermenter bucket:
Wash and sanitize a 2 gallon plastic fermenter, lid, stopper, air lock, and wire strainer.
Place raisins, acid blend, and yeast nutrient into the plastic fermenter.
Affix the stopper to the lid of the fermenter, cover and set aside.
Once the hour is up, use a slotted spoon to remove all of the ube pieces. Discard.
Add the sugar to the pot, stir well, and continue simmering until sugar is dissolved. Remove from heat, allow to cool.
Note: It doesn’t have to be all the way to room temperature, just cool enough that if it splashes on you, it won’t hurt - that’s a good guideline!
Line the sanitized wire strainer with cheese cloth.
Carefully strain ube water into the fer.menter, discarding the cheese cloth and any sludge that it caught.
Affix air lock to lid, cover the bucket, and allow to fully cool over night. For the sake of consistency in readings - and therefore accuracy in ABV calculations - this should be done where you plan to let the wine ferment for the next few months - usually a basement.
The next morning, check the Specific Gravity and write it down in your notes, along with the date.
Add yeast to the fermenter bucket, stir with a long, sanitized spoon. Affix the lid, allow to sit for 24 hours.
The next day, check to make sure that the yeast has started fermenting - there should be bubbles in the airlock, and/or foam in the liquid.
Put the lid back on, allow to ferment for one week.
After a week or so, use your sanitized siphon setup to rack the must into a freshly sanitized carboy. Put the carboy somewhere cool (not cold!), and leave it alone for a month or so.
Using sanitized equipment, rack the stone fruit wine off the sediment, into a clean, freshly sanitized carboy. Cap with sanitized airlock, leave it alone for another 1 month.
Rack one more time, leave it for another 2 months or so.
When your wine has been racked a few times and shows NO more fermenting activity for a month or so (no bubbles in the airlock, no more sediment being produced, you can move on to bottling.
Follow the instructions on your selected type of wine stabilizer to stop fermentation from restarting. For potassium sorbate, this needs to be done 2-3 days before bottling.
Using sanitized equipment, take a gravity reading if applicable, then back sweeten as desired, using sanitized equipment.
Using sanitized equipment, rack the wine into clean, sanitized bottles. Cork.