Preservation of Pear Juice and the uses of Malic/Citric acid

Preservation of Pear Juice & the uses of Malic/Citric Acid

 

We have had many enquiries about the preservation of Pear juice, which when pressed has a low acidity level and therefore can readily spoil.  So, we sought the advice of a microbiologist who formerly worked at the Long Ashton Apple Research Station.

Instructions for adding Malic/Citric Acid to Pear Juice

 

1. Press the Pears
2. Test the pH level (we sell pH meters/pH indicator strips, and the necessary buffer solutions) – the ideal reading should be less than or equal to 3.6
3. Test the acidity level (g/L) using the Aciquick test – the ideal reading should be 4g/L or just over
4. If the pH level isn’t low enough and you find that you have low acid, calculate how much acid (citric & malic) you need to add to your batch of juice to increase the acid level to 4g/L. For example, you have presses 100 litres of juice and the pH level isn’t low enough and the acid level is a low 1g/L. Subtract the actual acid level from the ideal acid level to calculate the amount of acid (malic & citric) you need to add per litre of juice: 4-1=3g/L of acid to add. Multiply the amount of juice that you pressed (litres) by the g/L of acid you need to add: 100x3=300g of acid (50/50 mix of malic and citric = 150g of malic and 150g citric). It is important to mix the malic and citric acid together in a little warm water until it dissolves, then add to the juice and stir thoroughly.
5. Now test the pH level again to check that it is the ideal level*. If the pH still isn’t low enough, repeat step 4 by adding more malic and citric acid.
6. This can then be pasteurised at the same temperature and time as is recommended for apple juice; i.e. 75° C for 20 minutes.

 

(*) It is interesting to note that there is no direct relationship between the pH and the acidity of juice, therefore, the above instructions must be conducted with a certain amount of trial and error.

 

Citric Acid can also be used in the making of Elderflower Cordial and to raise the acidity level of other low acid fruits e.g. in Strawberry Juice & Jam making, with Bilberries/Blueberries etc