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How to sterilise jars

blog Cleaning info Safety

When fermenting it is important to ensure that your jars are nice and clean in order to avoid contamination, it is not vital that they are sterilised they simply need to be clean but as we get a lot of enquiries on how to sterilise we decided to do a blog on it. 

Please be very careful when doing this as the jars will be HOT! The first process of sterilisation, regardless of which method you choose, is to check the jars or bottles thoroughly for damage such as cracks, breaks, and chips. If you find any of your jars or bottles are damaged you must discard them. The heat of the sterilization can break or explode damaged jars. Please note NEVER pour boiling water directly into anything Made of glass. This WILL cause the jar to crack. 

Method 1: The oven

Heat oven to 140C/120C fan/gas 1.

Wash the jars in hot, soapy water, then rinse well. Place the jars on a baking sheet and put them in the oven to dry completely. If using Kilner or kilner style jars, boil the rubber seals, as dry heat damages them. If there is a tap on the jar make sure you remove it first as this will melt in the oven. The tap can be sterilised in sterilizing fluid they are not suitable for using heat (however they do not generally need to be sterilised), leave in the oven for about 15 mins.

washing jars

Once the jars are removed from the oven they are ready to use HOWEVER please be careful as the jars will be hot and ALWAYS allow the jars to cool before adding any cultures as the heat will kill the culture.

jars in the oven


Method 2: The Water bath

Remove the lids or rubber seals from your jars and put to one side. Then place the jars into a large pan and fill with water until the jars are covered. Bring to the boil and keep at the maximum temperature for 10 minutes, turn the heat off and cover the pan to keep the jars warm until you are ready to fill them.

Place vacuum seal lids or rubber seals in a small pan and fill with 4 inches of water, heat and simmer at 82 degrees for 10 minutes, turn the heat off carefully remove the jars (use Tongs as they will be hot!) leave to cool before use.

water bath


Method 3: The Dishwasher

Remove the lids or rubber seals from your jars, wipe the rim and threads of the jar to remove any food debris and place everything into the top rack of your dishwasher and run it on a hot wash. No detergent or cleaning solutions should be used. 

Leave the jars to cool and then use.



Always ensure the jars are cool/cold before using. Plastic taps are usually dishwasher safe but wooden taps are not. 


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