Does anybody have any tips for making a good wine from wild grapes (vitus riparia)?
Sure, it’s not that difficult. You’ll need to be able to measure the titratable acidity of the grape juice and brix/specific gravity. Wild grapes can be pretty darn acidic, and the simplest way to reduce the acidity is to dilute the juice with water. Of course, that’ll dilute the flavor as well, so you might want to consider deacidifying with some calcium carbonate. If you don’t want to mess with chemicals, diluting with water still works pretty well. I think (going off memory, it’s been a few years) you’ll want to shoot for something around 6 g/L titratable acidity for the wine to be balanced.
You also will want to increase the sugar content of the grapes by adding table sugar, especially if you diluted with water. A good target is 22-23 Brix (1.09 - 1.095 SG).
You can certainly let the wild yeast on the grape skins do their thing, but it wouldn’t be a bad idea to get a sachet of wine yeast to make sure the wine ferments completely.
Thanks! I was looking at recipes and the amount of grapes ranged from less than 20 to over 40 pounds for a 5 gallon batch. I guess the low end would take care of the acidity with dilution but the high end recipe said nothing about even testing the acid level. Is there some other method of dealing with the acid?
I’m hoping that @tim_vandergrift responds because I’m sure he has tons of info, but the easiest way to reduce the acidity of any grape is to let them ripen as much as possible, as the acidity plummets the longer they sit on the vine. But depending on when you get frost, that might not be practical.
Another thing you could do is to put the wine through a malolactic fermentation, which converts the malic acid into lactic acid and reduces the sharpness quite a bit. Usually this is done by pitching a culture of oenococcus oeni, but these bacteria can be extremely fussy and only ferment under the right conditions. If you’re up for an adventure, though, you could pitch a pedio culture, which by some accounts is even better at malolactic fermentation and survives under much broader conditions. I haven’t tried this yet, but it’s definitely on the to-do list!
Thanks for the help. I am going to wait until we have a frost to harvest the grapes and then test the acidity. Hopefully I can make it with a minimum of dilution.
Sorry to be late to the party: been busy with wine!
First, are you sure it’s Riparia? That’s a pretty narrow category of grapevines–I’m more curious than anything. In any case my recipe is cribbed from my friend Jack Keller, who knows more about native grapes than anyone I know.
For five gallons
- 50 lbs Grapes
- 7-10 lbs sugar
- 3-1/2 tsp pectic enzyme
- 1/4 tsp potassium metabisulfite
- Acid blend (see below)
- 5 tsp yeast nutrient
Also about 2 to 2-1/2 gallons of topping water and yeast of your choice (can never go wrong with EC1118)
Crush and destem the grapes, and pull off enough juice to get an sg reading. Add sugar to the must (use dextrose because it dissolves easily) to bring the sg to 1.090–one pound of sugar per gallon will add 1.042 sg. Add enzymes and sulphite, stir hard and pitch yeast.
Punch down cap twice a day for 7 days, or until sg is below 1.010, press off grapes and top up pail to 5.5 gallons (losses will happen). This bit is important: for every gallon of water you add, add 2 lb of sugar–measure carefully, because you need this for alcohol content.
Measure the TA: if you picked after frost, you may need to add a bit due to watering back. Get in a range of 5.5-6.5 g/l. Use tartaric, because you can cold-stabilise later and drop the pH a bit more if it’s an issue.
Let sit for three more weeks to finish fermenting and drop gross lees. Rack into a 5-gallon carboy, add 1/4 teaspoon of sulfite and top up if necessary. In three months rack again, add fining agents, adjust sulfite to a pH-appropriate level, and in a month or so when it’s clear, go to the bottle.
Riparia isn’t to my taste, but I will say that well-aged examples (3-4 years) are a lot more palatable than anything younger. However, if you’re going to back-sweeten, you can drink it as young as you like.
Hope that helps out.