How much pumpkin and acid?
This isn’t a common wine to make, even for a country wine, but I did find some recipes. Every single one of them agreed on using 5 lb/Gallon (600 g/L) of pumpkin, but they were very different in the amount of acid and sugar. I think it makes sense to use the 5 lb/Gallon of pumpkin, but aim for the acid and alcohol profile of a white wine. That means aiming for a specific gravity of 1.090 and a titratable acidity of 7-9 g/L. Adjusting the acidity will be pretty easy. After preparing the must, titrate a sample to get the TA, then add enough acid to bring it into the desired range. I can’t do the same thing with the sugar, though, because I’ll have to add so much of it. The 2-3 lb/Gallon (250 – 350 g/L) I expect to add, and the 2-3 cups/Gallon (125 – 200 ml/L) of water to dissolve it in, will increase the volume of must by 40 – 55%.
How much sugar?
That means I need to work backward from the total amount of sugar I want in the must. An SG of 1.090 implies 2 lb 6 oz of sugar per Gallon (284 g/L) of must. So if I knew how much sugar was in 5 lb of pumpkin flesh, I would subtract it from the total. How much sugar is in pumpkin flesh? On average about 4 – 6% by weight, so our 5 lb would contain about 3.2 – 4.8 oz (90 – 135 g) of sugar – lets call it 4 oz (110 g). Mashing the pumpkin will probably double that to 8 oz. That’s low enough that we could ignore the pumpkin’s contribution and still get pretty close, but now that we know let’s take that into account. For every gallon (3.785 L) of must, we’ll need 1 lb 14 oz (850 g) of sugar.
Putting it all together
In order to get a gallon of finished wine, I like to make my “1-gallon batches” anywhere between 1.25 and 1.5 gallons. You’ve heard of a “bakers dozen?” Think of this a the “winemaker’s gallon.” For 1.25 gallons (4.7 liters) of must, we’ll need 6.25 lb (2.8 kg) pumpkin flesh and 2 lb 6 oz (1075 grams) of sugar.
6.25 lb (2.8 kg) pumpkin flesh
2 lb 6 oz (1.075 kg) sugar
tartaric acid to 8 g/L
2 tsp (10 grams) DAP
0.25 tsp (0.6 grams) tannin
1.25 tsp amylase enzyme
1.25 tsp pectic enzyme
sulfite to 50 ppm (equivalent to 1 campden tablet)
Premier Cuvee yeast
Remove the seeds from a pumpkin and peel it to get the flesh. Grate the flesh and bake at 350F (177C) for 30 minutes. Transfer to a pot and add amylase enzyme and enough water to cover. Heat to 150F (66C) and hold for 30 minutes.
While the pumpkin is baking/mashing, dissolve sugar in about a quart or a liter of water. Boil, then cool.
Strain the mash into your primary fermenter, add the sugar-water, then add cool enough water to bring it up to 1.25 gallons (4.7 liters). Add sulfite equivalent to one campden tablet.
When the must has cooled to about 70F (21C) or cooler, draw off a sample for testing. Measure the specific gravity (SG), the pH, and the titratable acidity (TA). Make a note of the SG.
Since we’re targeting a TA of 8 g/L, subtract the TA you measure from 8. Then multiply that number by the volume of must, in liters – 4.7 in this case. That will give you the amount of tartaric acid, in grams, to add to the must. There are about 5 grams of tartaric acid in a teaspoon, so you can divide the grams of tartaric acid by 5 to get the number of teaspoons. For example, if the TA is 2 g/L, then you would subtract 2 from 8 and get 6 g/L. Multiply this by 4.7L to get 28.2 g. Divide that by 5 g/tsp to get 5.64 teaspoons. I don’t know about you, but I don’t have a “0.64 tsp” measuring spoon, so we can round that to 5.5 tsp.
Thoroughly dissolve the tartaric acid, pectic enzyme, tannin, and DAP in a little water and add it to the must. Measure and record the pH. The TA should be 8 g/L. Cover and wait three hours for the pectic enzyme to work, then pitch the yeast.
It’s a bit more involved than other wines, but now that you know how, don’t you want to pour some pumpkin wine on Halloween?