Question: how long does it take for cranberry juice to ferment?
Answer: Cap with a water lock and allow the mixture to ferment in primary for 2-3 weeks. Alternately, allow the mixture to ferment without an airlock for about 5 days, then rack into secondary and add an airlock. Either way, once the mixture is in secondary, add an airlock. Ferment in secondary for 6-8 weeks before bottling.