Washington Winemaker

I’ve been anticipating this since May, and now it’s finally time to make Rhubarb Wine. I grow the rhubarb in my garden, harvest several times (freezing each harvest), and make a gallon or two of wine every year.

Ingredients For 1.5 gallons (about 5.7 liters) of must

3-4 lb (1.4-1.8 kg) rhubarb
Sugar to specific gravity 1.090 - up to 4 lb (1.8 kg) sugar
0.125 (0.3 g) tsp tannin
1 tsp (5 g) diammonium phosphate (DAP)
1 tsp (2.3 g) pectic enzyme
sulfite to 50 ppm (equivalent to 1.5 campden tablets)
yeast

How do you juice rhubarb?

I’ve tried things like cutting it up and putting it in a blender and soaking in water. The best ways to “juice” rhubarb are freeze/thaw and sugar extraction. I usually do both. As you harvest the rhubarb, wash it and cut it up into 0.5 inch (1.25 centimeter) pieces and freeze them. When you are ready to make wine, thaw the rhubarb and put it in a strainer. I usually get 2/3 - 3/4 cup/pound (350-400 ml/Kg) of rhubarb juice this way. Once you’ve strained the juice, sulfite it. Next, place the rhubarb in a container and cover with about 1 lb (about 450 grams) of sugar. Let it sit until the sugar has dissolved (about two or three days), then strain off the liquid. Place the rhubarb back in the container and cover with water for a few hours or overnight. This is a rinse to get every last bit of “rhubarbness.” Strain the liquid and discard the spent rhubarb. At this point, I dissolved the tannin, DAP, and pectic enzyme in 0.25 cups (about 60 ml) of water and added it to the liquid.

Measure then adjust the sugar

I repeated the sugar extraction step, so I used 2 lb (about 825 g) of sugar, and ended up with 2.36 quarts (2.23L) of SG 1.114 liquid. I’m going to switch to metric measures, because calculations are easier, and report numbers with much more precision than I can measure so that I don’t carry rounding errors from one step to the next. I’m aiming for 5.68L of must with an SG of 1.090. Adding 3.568L of SG 1.075 sugar water will yield 5.8L of 1.090 must. An SG of 1.075 implies 232 g of sugar in each liter of solution (not 232 g added to 1L of water!). So 3.568L at 232 g/L means 828 grams of sugar. I boiled 1L of water, took it off heat, dissolved the sugar, and brought it back to a boil. Once it was boiling, I took the pan off the heat and cooled it in a water bath for 15 minutes. I used a measuring cup to determine the volume of sugar water (1.45L) and added it to my fermenter. Then I added tap water until I reached 3.568L total.

I added the sugary rhubarb juice to the sugar-water in the fermenter and measured the specific gravity. I should have 5.8L of SG 1.090 must, and I measured the SG as 1.095 - my kitchen scale and measuring cups were never going to be very accurate, so I’m calling that good!

What about the pH and titratable acidity?

If you’ve read many of my posts, you’re probably wondering why I haven’t mentioned the acidity of the must. I’m always going on about how important pH is to stability and titratable acidity (TA) is to taste. What’s going on? I’ve made rhubarb wine for years, and I’ve found that using rhubarb at a rate of 1.5-3 lb/Gallon (180 - 360 g/L) of must consistently gets me close to 6 g/L acidity. So I’ve decided to wait until it ferments out, then measure the acid and make any corrections.

Isn’t the oxalic acid dangerous?

Some wine makers neutralize virtually all the acid in rhubarb, then add back acid (tartaric, citric, or a blend). They do this to remove the oxalic acid, which is toxic and present in rhubarb. Removing the oxalic acid will change the wine; I think it detracts from rhubarb’s unique character. Most of the oxalic acid is in the leaves, and I make rhubarb wine with the stalks only (so should you!). It’s true that the stalks contain some oxalic acid, and while I don’t know what the precise amount is or exactly how much of this acid can be dangerous, I can tell you that I’ve made - and consumed - rhubarb wine this way for years with no ill effects. Obviously, I wouldn’t be doing this if I thought it was harmful, but you’ll have to make your own judgment about that.

With nothing left to do, it’s time to pitch the yeast. They’re the real wine makers, and they should have this must turned into wine in the next week or so. Then I’ll rack as needed, and bottle in about a year. It’ll be drinkable soon after that, but it ages very well, so keep a few bottles if you can.

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