How to Know If Your Cider Has Gone Bad

How to know if your Cider has gone Bad

Occasionally when making cider from home, things can go wrong and the finished product can end up bad. It’s inevitable that there will be occasions when things don’t go to plan, so we’ve put together the signs you should look out for.

Slimy Pulp

You’re unlikely to experience slimy pulp if you use genuine cider apples and don’t keep them stored too long. If you use dessert apples, there is a tendency for pectin to leach out the cells of the apples and be partially broken down by the natural fruit enzymes. This results in a layer of slimy pulp which will clog up press cloths and make it extremely difficult for the juice to soak through. Using a mixture of different apples will help to offset the poorer characteristics of the dessert fruit.

Fermentation & Storage Issues

It’s unlikely for problems to arise in a good and active fermentation. For those that prefer a slow fermentation or early storage, there are three problems that could arise. Film yeasts contaminate slow and unsulphured fermentation, as well as cider that has been stored in a way so that air cannot get in. The organisms present here are on the fruit, and they thrive in aerobic conditions. This means they can appear on top of the liquid and will begin to break down the alcohol. You should notice its presence, but you’ll be able to detect it by a strong smell of ethyl and amyl acetates. These compounds are important attributes to the flavour of cider, however, when it becomes noticeable, you have a problem. The yeast itself will form a powdery film on the surface of the cider which will slowly break up into small, white bits and drop to the bottom. Equipment, where infection has occurred should be sterilised before reusing.

Cider Sickness

Cider sickness is a disorder that is caused by a bacterium known as Zymomonas. This bacteria ferments sugars in the same way as yeasts, but it also produces many acetaldehydes which can be detected by its smell- similar to lemon and banana skins. Acetaldehyde also combines with the tannin present in cider and gives off a milky haze, turning the cider thin and bland. This problem only affects sweeter ciders or those with residual sugar. The recommended treatment for cider treatment is to raise acidity to 0.5% and to add an active fermenting yeast. Again, all equipment that has been affected by cider sickness should be fully sterilised before reusing.


A cider can be unaffected by haze in small amounts. Microbial hazes are often caused by spoilage yeasts or heavy infestations of bacteria, including a slow-growing yeast that forms clumps in unsweetened cider at the bottom of its bottles. Though it doesn’t affect the flavour much, microbial problems should be avoided. The only reliable to tell if a hazy cider is microbial in origin is via a microscope. As this is impractical for the domestic cidermaker, it’s best to go with your instincts and to be safe.