Apple jam has fermented in jars. Gas, foam, or a sour smell has appeared in the sweet preserve. You opened the jar and are unsure whether it is still safe to eat.
Check smell and gas. If there is hissing, foam, or an unpleasant odor, do not consume.
Gas, foam, or a sour smell appears in the sweet preserve.
Smell, gas, foam, slime, and mold are key indicators of spoilage.
Fermentation in sweet preserves usually indicates spoilage.
If you are unsure, it is safer to discard the product.
If in doubt, it is better not to take the risk.
Due to improper storage conditions or loss of seal.
These pages help you quickly understand related risks and common mistakes that often appear together.
A dry ring formed on top of an opened jar: what it may mean, what to check first, and when it is better not to risk consuming the product.
Check smell and gas. If there is hissing, foam, or a strong unpleasant odor, do not consume.
An opened jar was stored too long in the fridge: what it means, what to check, and when it is unsafe to eat.
Check smell and gas. If there is hissing, foam, or an unpleasant odor, do not consume.
What happens if preserves are stored in heat and when it becomes unsafe.
If preserves were stored in warm conditions, the risk of spoilage increases—do not consume if there are any warning signs.