Length of fermentation for cider

Question

Newbie homebrewer working with store bought apple juice for my first test batch.

How long should fermentation take?

About 5 days ago I added my yeast to 4 litres of apple juice, and it looks like the fermentation is already coming to a stop. It has slowed to the odd intermittent bubble. Is fermentation already complete? I was expecting fermentation to take two weeks or so, but has this been impacted by the low volume (only 4 litres)? Also, I added in way too much yeast to begin with: might this have shortened the length of fermentation (ie. burned through the sugar too quickly)?

Thanks in advance.

Answer 1

primary fermentation is often over in (say) 5 days. The best way to check fermentation has finished is to take several successive specific gravity readings with a hydrometer (or a refractometer) and if the reading is stable for two days then the fermentation can be deemed to be finished.

It may be worth noting that store boght juice can be pasteurised and so be "sterile" with no chemical additions or the juice may contain preservatives that can interfere with fermentation. That can be worth checking before buying. Most store bought apple juice in the UK seems to be amazing uniform in sugar content and is usually pasteurised. One might suspect it was all premixed ready for industrial cider production.

It might be worth noting that nicer cider is obtained by letting the young cider age for 12-18 months in the bottle before consumption. Some of the nicest cider I have ever tasted was made from freshly crushed apple juice and no added yeast at all. Just that which was in/on the apples and crushing press.

Answer 2

Yes, it's very likely fermentation is done.

For example 1 gallon juice and 1 pack of bakers yeast only takes 3-4 days.