The Four Spoilers

When making preserves good hygiene is essential. There are four micro-organisms known as 'spoilers' which if they make their way in to your preserve will ruin them making them inedible. The four spoilers are Enzymes, Bacteria, Mould and Yeast. These are not things which you need to be frightened of provided you follow the simple rules below.

We will tell you a little about each spoiler and give you some easy tips which will help you avoid them ensuring you can get full enjoyment from your homemade preserves.

Enzymes are proteins which are found in all living things, animal or vegetable. Enzymes are catalysts which trigger change such as deterioration i.e. when damaged fruit or vegetables start to discolour.
Enzymes are most active at temperatures between 29 and 50 degrees, however they will be destroyed at temperatures over 60 degrees.

Bacteria are only visible under a microscope, they increase rapidly at temperatures between 20 and 40 degrees but are killed at temperatures over 100 degrees. Bacteria cause food to rot so it is vital that these are destroyed during the preserving process.

Mould spores will settle on any fruit and vegetables and start to form a green/grey cotton wool like appearance on the surface. Mould thrives at temperatures between 10 and 38 degrees but can be destroyed at temperatures between 60-90 degrees.

Yeast when found in food is generally not harmful to our health but it can cause food to spoil. Most yeast will grow in food containing over 60% sugar if it is badly covered and air is allowed to get to it but it can be destroyed at temperatures above 60 degrees.


Avoiding The Four Spoilers

Now you know a little more about the spoilers, there are ways to avoid and eliminate them from your preserves. 

Just follow these simple preserving rules:

  • Have good hygiene - all equipment and work surfaces need to be thoroughly cleaned and jars must be sterlised before and after being filled.
  • Use high temperatures - this is an integral part of the preserving process as it is paramount in destroying these spoilers. The Kilner® Preserving Pan, funnels and jars are made to withstand high temperatures required in the preserving process making them the ideal tools for the job.
  • Ensure high concentrations of either sugar, acid, alcohol or salt in preserve mixtures as they are important to kill off the spoilers.
  • Create an airtight seal - air must be excluded from the finished product. Kilner® Jars are ideal for creating an airtight vacuum seal provided you follow the filling and closing instructions provided. Find more information on how to do this on our Making your First Preserve guide.

Provided you follow these simple tips along with your recipe your preserves should remain 'spoiler' free.