As an expert sommelier and brewer, I can assure you that it is generally safe to drink fermented apple cider. When apple cider undergoes fermentation, it means that the natural sugars in the cider are being converted into alcohol by yeast. This process is similar to what happens when making wine or beer.
During fermentation, various compounds are produced, including alcohol, carbon dioxide, and organic acids. These compounds contribute to the flavor and aroma of the cider. However, if the fermentation process is not properly controlled, some unpleasant flavors and aromas may develop.
One of the most common issues that can arise during fermentation is the production of acetic acid, which gives the cider a sour taste, similar to vinegar. While this may not be desirable for most people, it is not harmful to consume. It simply means that the cider has undergone an extended fermentation process and has a higher level of acidity.
It's important to note that the sour taste and increased acidity do not necessarily mean that the cider has spoiled or become unsafe to drink. It may simply taste unpleasant and different from what you were expecting. However, if the cider has an off-putting smell, mold, or visible signs of spoilage, it is best to discard it, as these could be indicators of a more serious issue.
In terms of alcohol content, fermented apple cider will have a higher alcohol percentage compared to non-fermented cider. The exact alcohol content will depend on various factors such as the initial sugar content of the cider and the yeast strain used for fermentation. Typically, fermented cider will have an alcohol content ranging from 3% to 8% ABV (alcohol by volume).
It's worth mentioning that consuming excessive amounts of alcohol, regardless of its source, can have negative health effects. Moderate consumption is generally considered safe for most adults, but it's important to be mindful of your own tolerance and limits.
Fermented apple cider is generally safe to drink, even if it tastes sour and has a higher alcohol content. However, it's important to use your own judgment and discard cider that shows signs of spoilage or has an off-putting smell. Enjoying cider in moderation is key to maintaining a healthy relationship with alcohol.