Here is the basic process for fermenting fruit into wine or cider.
Preparing the Fruit
How the fruit needs to be prepared depends on the type of fruit and what you are hoping to make.
Starting with Juice: Apple cider and pear cider both are typically made from pressed juice. This is because the hard fruit would not be easy to juice after the fact. You can buy wine making juice for particular strains of grapes at your local home brewing supply store. These are handy if you want to make a specific type of wine. To make white wine you must start with just juice otherwise you end up with something that is more like a pinot noir.
Starting with a Fruit Mash: Soft fruits (including grapes) can be fermented whole. Just start with a process of de-steming, washing then gently crushing the fruit. The fruit is then mixed with sugar, boiled water and yeast (depending on the recipe) and allowed to ferment in the open air for up to a week. You will need to filter the juice out from the solids for the primary fermentation process. It’s best to start by removing the floating solids before gently pouring off the liquid. You don’t need to extract every little bit of liquid, so leave the solids at the bottom of your container rather than trying send all the liquid through a sieve. Otherwise it can be very frustrating.
Once you have your juice ready for fermentation you need to mix it with sugar and yeast, according to your recipe, and put it in a fermentation vessel. You should see it bubbling in the airlock for 2 weeks. It is best if you can keep your ferments somewhere cool (approx 15 C / 60 F to 23 C / 75 F). If it’s too warm, then the fermentation process will go quickly and the resulting drink won’t taste as good.
Let it sit for a week longer after the bubbling as stopped before racking.
Racking is a way of clarifying your wine or cider. Once it’s stopped it’s primary fermentation it’s officially finished. However, it’s a good idea to let is age a while longer to allow the suspended yeasts to filter out and develop the flavour.
Rack the cider/wine by transferring the liquid into a clean vessel with an airlock for another month or two. If you want a very clear wine you may have to rack 3 or 4 times. For cider you generally only rack once before bottling it. The sludge of expired yeast tastes bad, so I do recommend that you rack everything at least once.
You want to prevent oxidation when racking, so be sure to siphon the liquid into the bottom of the jug to prevent splashing.
Bottling and aging
Cider: If you want your cider to be sparkling, then you need to add more sugar at bottling time so that the residual yeast can ferment the sugars. At that point you will need to age it for at least 2 more weeks before drinking.
You will need to store your cider in plastic bottles or swing-top bottles that are built to handle the build up of carbonation. If you are doing a large batch of glass bottles, do at least one plastic bottle so that you can test the carbonation by seeing how firm the bottle becomes. Once the carbonation has built up, store the cider in the fridge to prevent it from building up too much pressure. You don’t want your bottles of cider exploding before you get the chance to drink them!
Wine: White wines generally age in the carboys for 3-6 months before bottling, and red wines age for 6-12 months. During this process you would have to rack the wines several times, leaving behind all the sludge at the bottom of the fermentation container.
When it is finished you can bottle the wine in the traditional glass bottles with a cork or in swing-top bottles. It won’t build up carbonation so you don’t need to worry about storing it in the fridge.
As long as conditions are right, yeast will keep fermenting until all of the sugar is gone or until the ferment reaches alcohol levels of around 17%-20%. The exact amount of alcohol percentage actually depends on the strain of yeast. For example, wild yeasts usually die off at 5% alcohol, but champagne yeast is about 20%.
If you don’t want your wine or cider to be dry (with all the sugar having been consumed by the yeast), then you need to prematurely stop the fermentation. In the case of cider, the easiest way to stop the fermentation is to refrigerate your cider once it has carbonated. Dry red wines don’t require you to stop the fermenation as they will naturally end when all the sugars have been used up. However, sweet white wines and red wines need to have the fermentation ended early through the addition of sulfur dioxide.
Add sulfur dioxide to sweet wines at the first point of racking (you should check the alcohol level and sugar levels first). Calculating how much SO2 to add isn’t completely straight forward, so I won’t delve into it at this point. My goal for this initial foray into wine and cider making is to do recipes that are simple for the average DIY home brewer. Maybe next year I will get into the nitty-gritty of wine making chemicals.