Frequently Asked Questions

Frequently Asked Questions


Q: What is Certo made of?

A: Certo is made from the residue of pressed citrus fruits, which are rich sources of pectin.

Q: Is Certo a natural product?

A:  Certo is manufactured from natural citrus fruit pectin. Certo requires a minor adjustment in acidity (by adding citric acid and potassium citrate) to assist in setting performance and the addition of a small amount of preservative (potassium sorbate).  Therefore, under UK guidelines, Certo cannot be described as completely ‘natural’, but is naturally derived.

Q: Is Certo suitable for Vegans?

A:  Yes!  Certo is made from naturally sourced pectin and no animal products are used in the production of Certo or its packaging so it is totally suitable for vegans.

Q: Does Certo contain any genetically modified ingredients?

A: No


Why do I need to add Certo when making jam?

A: There are two main reasons;

1) Fruit that is very ripe loses its natural pectin and hence the ability to set.

2) Certain varieties of fruit contain little natural pectin, e.g. strawberry.

Q: I have added Certo, but my jam has not set properly?

A: There are three main reasons:

1) Occasionally, the fruit has to be boiled longer than stated in the recipe due to natural variations in water content or an excess of water left on the fruit after washing.  Do not be tempted to add more Certo. This will not help achieve a set.  Bring your jam to a hard boil for an additional couple of minutes and test for a set.

2) Fruit that is very ripe or of a particular variety can be lacking in pectin and natural fruit acids. The addition of lemon juice (see below) will ensure setting or you may need to boil your jam for a little longer to achieve the set.

3) It is also important not to disturb the jam once it is put into the jars until it is quite cold and has set properly – this will take some hours, and the jars are best left overnight if possible before moving them.

Q: Does ‘fresh` lemon juice need to be used when making jam with Certo?

A: Freshly squeezed lemon juice is preferable, but bottled lemon juice works as well. If natural acid is lacking then lemon juice is needed to increase the acidity to help the set.

Q: How does Certo affect the quality of jam?

A: Certo recipes are constructed to require an absolute minimum boiling time for the fruit, which preserves both colour and flavour and hence results in a better quality jam.

Q: What are the benefits of making jam using Certo compared with using other brands of pectin pre-mixed with sugar?

A: Because the pectin is added at the end of the cook, no destruction of the pectin by heat can occur. When the pectin is combined with the sugar, it is in the pan right through the boiling process, and this can damage the pectin.

Q: Can I increase the fruit content of my jam? Do I have to adjust the amount of Certo used?

A: The main problem with increasing the fruit content in a jam is that fruit contains a great deal of water. Increasing the fruit content means that more boiling will be required, which will impair the colour of the jam, and in many cases the flavour also. For this reason, we do not recommend that you change the Certo recipe by adding more fruit.

Q: Hi. I made 10 lbs of grapefruit and lemon marmalade and put one bottle of certo – I felt this was sufficient as marmalade usually sets. I’m recooking it now. How much more Certo should I use? Will the Certo already in there work if it is boiled again?

A: Don’t add any more Certo, as this will then need more boiling as Certo is almost 90% water. The Certo already there will work well after a short re-boil. Just put the marmalade back into a really large pan without adding any water, heat to the boil stirring to prevent burning, then boil as fast as possible for a few (perhaps 3-4) minutes. Check a small sample for a set, and if OK, pot up again. If not setting, you can boil for a few more minutes.

Q: Who do I contact with a “how to use” enquiry?

A: Dr Colin May is a leading world authority on pectin and an enthusiastic home jam maker. He would be happy to help with any “how to use” enquiries. (See CONTACT US page.)


Q: Why does Certo need to be refrigerated after opening and used within 14 days?

A: Certo is a dilute solution of pectin and sugars from citrus fruits. It is an ideal medium for yeasts and moulds that could destroy the pectin and turn the sugar into alcohol. There is enough preservative to stop this happening immediately, but only if the Certo is kept refrigerated, and used in a limited time.

Q: I have noticed sediment in the bottle; what is it and does it affect the quality of the Certo?

A: This may be very small amounts of dissolved pectin powder. It is harmless and has no effect on the quality or effectiveness of the Certo.  In all instances you should shake the bottle well before use.

Q: My Certo has passed its “Best before date”.  Is it still safe to use?

A: It will not do you any harm, but it is likely to give a poorer set to your jam. It is best to get fresh supplies of Certo from our on-line shop .

Q: Where can I buy Certo?

A: Certo is available from all major supermarkets, wholesalers and independent shops.  If you are having problems buying Certo you can now buy from our on-line shop Is super easy and efficient !

Follow Us

Got Lots of Fruit ?
Search for a Recipe:

Recipe Book

If you would like to download our recipes as a PDF please CLICK.


Take A Survey

Please help us to improve by completing a short online survey

Quick Links

Don't be a stranger!

Send us a Quick message

We are always happy to answer any questions you might have. 

Shopping Basket