Winemakers will often say that anything can be turned into wine, and a watermelon is no exception. Success with this wine starts with choosing the right melon. The remainder of the process uses typical good winemaking procedures. While not difficult to make, an initial trial batch of grape wine is good practice before tackling a more exotic watermelon wine.
Making Watermelon Wine
Finding the right watermelon is more art than science. Visit a farmer's market to find the best melons. Growers are more knowledgeable and selective about the produce they sell, so buying directly from them gives you a better chance of finding a perfect melon. (See Reference 1)
A perfect watermelon feels heavy for its size, indicating the presence of lots of juice inside. A fully ripe field-grown melon will sport a creamy yellow patch on its underside where it rested on the ground. Use your open hand to deliver a firm thump to this side of the watermelon. If the thump produces a hollow sound, you have found a thoroughly ripe watermelon with lots of flavor.
Use the knife to cut the red fruit from the rind. Trim off any pieces of white pith that cling to the fruit and remove all the dark seeds. The rind and seeds will introduce an unwanted bitterness to your wine.
Place the melon chunks in a bowl and chop the fruit into small cubes. The bowl collects the juice as you chop. You should have about four pints of watermelon juice. (See reference 2)
Put the watermelon cubes and juice into a straining bag or a sieve. Squeeze the juice from the fruit into the bucket, your primary fermenter. Place the seedless and rindless pulp into a clean fermenter bag, which can be either a special-made polyester one or an old white pillowcase secured at the top with a string. (See Reference 3)
Add the tannin or tea, water, sugar, acid blend, yeast nutrient and campden tablet to the juice. Put the fermentation bag of pulp into the bucket and allow the string to hang over its side. Do not add the wine yeast at this time. (See Referene 3)
The campden tablet will destroy any wild yeast cells in the juice. Wild yeast cells give unpredictable results and produce off-flavors that will spoil your wine.
Stir these ingredients together well, cover the bucket with a clean towel and allow it to set for 12 to 24 hours. Sprinkle the wine yeast over the juice mixture. (See References 2 and 3) The yeast nutrient you added earlier gives the baby yeast cells a boost as the wine ferments.
Allow the wine to ferment for five to seven days, stirring it daily. Bubbles should appear on the wine's surface within the first day. The wine will bubble vigorously for a few days and then nearly cease. About 70 percent of the overall fermentation happens during this time. (See Reference 2)
When few or no bubbles appear on the surface or around the edge of the bucket, remove the fermentation bag, squeeze it to extract as much juice as possible from the pulp. Discard the bag and pulp.
Siphon the wine from the primary fermenter into the sterilized secondary fermenter, transferring only the liquid and leaving behind dead yeast cells and the remainder of the pulp, a sediment known as the lees. Do not worry if a little sediment finds its way into the fermenter, though.
When the wine has been siphoned into the secondary fermenter, attach the airlock to the top of it. Half-fill the airlock with water. The airlock allows carbon dioxide to escape while preventing spoilage organism and fruit flies from falling into the wine.
Allow the wine to undergo its secondary fermentation for about four to six weeks. Use the hydrometer to measure the wine's alcohol content, which should read between 0.990 and 0.998 on the equipment's specific gravity scale. (See Reference 3)
When the secondary fermentation is complete and the wine is clear, siphon it into another container, avoiding stirring up the bottom sediment. This is known as racking. Add cool boiled water to make up for any juice lost during this process.
Allow the wine to stand undisturbed for one month, racking it into another clean container. Repeat the racking process every three months for one year. At the end of a year, your watermelon wine is ready for bottling.
Your wine is drinkable at this stage, but the flavor improves if it ages another 12 months or more. (See Reference 2)
Keep all winemaking equipment spotlessly clean to avoid contaminating your product with wild yeasts and other spoilage organisms.
Use an airlock to allow carbon dioxide, a side product of fermentation, to escape. A tightly capped fermenter full of wine and carbon dioxide will explode.