Pretty much every jam or jelly you make will start to foam when it is boiling. You might be wondering why you should skim the foam off the top, it always seems like you are wasting a load of the jam.
What Is Jam Foam Made From?
Quite simply, the foam that rises to the surface whilst the jam is cooking is the air that is being forced out of the fruit by cooking and being trapped in the get that is forming in the jam.
There are a couple of good reasons to remove this foam and with a little bit of skill, it is pretty easy to get rid of all the foam that forms on your jams. Let’s take a look.
Why Skim The Foam Off Jam?
There are two main reasons for skimming your jam or skimming the scum as I sometimes call it and they are:
- Remove the air from your finished jam.
- Improve the texture of your preserves.
Removing Air From Jams
When it comes to any preservation, we want to limit oxygen exposure. Having air trapped in jars of jam is a likely point for spoilage microbes and moulds to form.
The foam on top of the jam when it is boiling, if not removed, gets transferred into the jars which are then sealed leaving tonnes of tiny bubbles of air in the jar.
It is, of course, impossible to remove every single trace of foam but by not removing the majority by skimming your jam you are more likely to see jars of jam that are more like to spoil or spoil quickly after opening.
Texture & Appearance Of Foam In Jars
The next reason for skimming the foam from your jams and jellies is to do primarily with taste and appearance.
The foam has a texture and colour that is different from the jam you are making. When you come to jar the jam any foam may not just be sitting on top but can run throughout the jar meaning it can interfere with the look and mouthfeel of the whole jar.
The best thing to do to avoid these problems is to remove the foam whilst it’s cooking.
How To Skim Foam From Jam
There is no right or wrong way to skim the foam from a jam. It is really a case of trying to remove the foam without too much of the jam itself.
The best way to do this is towards the end of boiling the jam before you are ready to add it into jars. Trying to skim too early and you’ll find more foam surfaces and you have to repeat the process.
- After boiling your jam for around 15 minutes you’ll have plenty of foam on the surface of the jam.
- Turn off the heat and use a large spoon to collect the foam into one area.
- Scoop the spoon underneath the foam as close to the surface as possible and transfer it to a separate container.
- Resume the boil and skim as necessary until you are ready to jar the jam.
Can You Do Anything With The Skimmed Jam Foam?
There is a trick for using the foam you have skimmed for the jam.
Place the foam in a microwavable container and microwave on full power for 30 seconds at a time. You should notice the bubbles dissipate and leave the foam looking just like the jam you are making.
I like to keep this in the fridge to use straight away rather than adding the foam back to the main pot.