two apple ciders with green tea and plum

How (alcoholic) apple cider is made

As a people we seem to have managed to make alcoholic drinks from just about all of our produce. Grains can be transformed into beer, or spirits such as whiskey. Grapes are transformed into wine and apples, yes, you guessed correctly, into cider. Making these foods into alcoholic drinks was a way to preserve them. But at times the drinks often were a safer alternative then dirty drinking water.

Apple cider is a quite refreshing drink definitely different from those other alcoholic drinks. Also, it seems that more new craft cider houses are popping up, so it’s about time to discuss how apple cider is made and where it comes from.

It starts with apples

All you truly need to make apple cider are apples and yeast (which might already be on your apples). As a result, the apples you use will heavily influence the quality and flavour of the final cider. There are a few properties that cider makers look at when choosing their apples:

  1. Acidity: this will impact the sourness and tartness of the final drink, you want quite some acidity but too much will make a tart undesirable drink.
  2. Sweetness: the sugar in apples is converted into alcohol during fermentation, so more sugar, generally means more alcohol
  3. Tannin content: tannins are a group of molecules that taste bitter and astringent, you want some of this for a more complex flavour but too much will not be desirable (tannins are also common in red wine)

There are apple varieties that are specifically grown for making into cider. These so called cider apples tend to be more tart and bitter because of their higher levels of tannins than regular apples. Therefore, often these apples won’t taste good when you eat them fresh. When you transform them into a cider though, you might be looking for some of those flavours to come through.

Apart from using just one apple variety, cider makers may also use blends of apples. Choosing a specific blend can give just those properties they are looking for that you can’t find in a single variety.

apples in bowl

Making apple juice

For the actual cider making you only need the juice of the apple, not the seeds, skins, etc. So once you’ve chosen your apples, you have to roughly grind the apples. This starts breaking down cell walls and the juice starts to come out. Once you’ve ground the apples this mixture is pressed to get out as much juice as possible. The juice will not be clear, instead, it will be hazy with particles floating around. In some cases cider makers will clarify the juice at this point but most do it at a later stage, or not at all.

Not all cider makers do this process in-house, some will buy the apple juice itself.

If you’ve ever eaten an apple you will know that if you take a bite out of the apple, and leave it out for only a little while, it will turn brown. This is caused by enzymes which initiate enzymatic browning reactions. Apart from turning brown, apple juice is also very vulnerable towards spoilage by micro organisms because of the high sugar content. Therefore, manufacturers will either use the juice directly or treat it to stabilize it.

What about the rest of the apple?

Apart from the juice, you’re left with apple remainders such as peel and seeds. These are called pomace. This is full of pectin and can be used for various other applications (which is what helps making pumpkin into a pumpkin pie and create a good texture of a fruit jam). However, it’s not required for making apple cider.

cider fermentation tanks
The cider fermentation stainless steel tanks as used by Eris cider house.

Fermentation of the apple juice

In order to convert the apple juice into cider, the apple juice has to ferment. During fermentation the sugars in the apple are converted into alcohol. Fermentation is essential for any alcoholic drink, whisky, beer, et.c all start out with fermentation.

Starting with a clean slate

In order for fermentation to occur the right types of yeast need to be present. Apples contain several micro organisms, including yeasts naturally. In some cases cider makers let these naturally present micro organisms do their work at this point.

However, in a lot of cases these may not be the right type and not give the desired flavours. Therefore, cider makers may first want to make sure that no undesirable micro organisms are present (including ones that can make you sick, pathogenic ones).

There are various ways to do this, the juice can be filtered (to take out some of that sediment which tends to contain more micro organisms) or pasteurized but the most common method is to add some sulphur dioxide (SO2). Sulphur dioxide kills of all micro organisms in the juice, allowing a cider maker to start with a clean slate. However, you will have to wait several hours before adding in your specific yeast to prevent it from being deactivated by the sulphur dioxide as well!

Initiating fermentation

At this point you are either ready for the natural yeasts to do their work or you can add your chosen yeasts to the apple juice. Choosing the right type of yeast can be pretty complex. The yeast needs to thrive in apple juice for one thing and needs to make the right flavour molecules that a cider maker is looking for. The type of yeast used will definitely impact the final result of your cider.

Once fermentation starts the yeast convert the sugars in the juice into alcohol, making a lot of flavours along the way. Apart from the yeast you choose, the temperature of the vat will impact the fermentation process. Higher temperatures result in faster fermentation for instance, but will give different flavours than a slower fermentation at lower temperature. Generally temperatures between 15-22C are used.

The fermentation process will last several days to weeks. By the end of it, you have an alcoholic apple cider.

Second fermentation

After a while the yeast starts to slow down since there is less food (sugar) available. In a lot of cases the cider is now transferred to a new tank for a second batch of fermentation. During this step not a lot of new alcohol will be formed but the flavour of the cider will continue to change. It isn’t uncommon for cider to be aged for several weeks in a tank.

Barrel aging

Instead of ageing the cider in another stainless steel tank, you can also age the cider in wooden barrels. Most cider makers will use oak barrels that have already been used for other drinks such as wine or whisky. These barrles contain a lot of flavour molecules from both the wood as well as the drink that was in there before so will really impact the flavour of your cider.

Adding flavours

You can also use this second fermentation or ageing step to add additional flavours. One option is to add hops, yes those are commonly added to beer, to your apple cider. Hops have a strong and complex flavour. By soaking it into the apple cider for a few days, the apple cider will get some of that hoppy flavour. Apart from flavour, hop can also help preserve a cider.

Another option is to add spices such as vanilla to the cider at this point. They will slowly infuse the cider with their flavours. You will also find ciders to which additional fruits (e.g. blueberries) have been added again at this point. Adding fruits though will result in more active fermentation again. Fruits contain new sugars so can revive the yeasts again! If a cider maker does not want this to happen, they can force the fermentation to stop first by adding chemicals that stop the yeast. They might do this for instance when adding back some apple juice if you want to sweeten up the cider slightly but not get more alcohol again.

Clarification

Remember that the initial apple juice if often hazy to start with? Most apple ciders though are clear and have no particles floating around. That is because they are clarified after the fermentation process. Some of the particles have settled down to the bottom of the tank (sedimentation), so those are easy to remove. Especially after quite long fermentation times, a lot of the particles will have settled out already. In other cases a centrifuge can be used to separate these particles or you can add ingredients that will gather these particles

See the process

Angry Orchard, a brand of alcoholic cider has a nice video on their website showing all the most essential steps, starting with the apples, ending with a cider.

Further reading

American Home Brewer’s association, The balancing act: how to make hoppy cider, Milly Shamburger, link

Want to make your own apple cider? How to make hard cider explains it well, they also explain how to back sweeten your own cider.

Looking for industrial equipment to make cider, GEA has a nice overview of the pieces equipment to be used.

Great review and in-depth discussion of various ways to make apple cider by Lallemand.

D. Arthey , Fruit processing, 2012, Springer science & business media, link

Ben Watson, Cider, Hard and sweet: history, tradition and making your own, 3rd edition, Chapter 3 & 4, link

Cidersage, How to make hard cider, link

Cider school, Cider apples, link

Jolicoeur, C., The new cider maker’s hanbook, 2013, link

Maria Kosseva, VK Joshi, PS Panesar, Science and technology of fruit wine production, chapter 3 & 4, link

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