In a large heavy bottomed saucepan, stew the fruit with the water and apple juice until the rhubarb has cooked through (roughly between 15-20 minutes, depending on the rhubarb).

Add the sugar and lemon juice and cook until the sugar has dissolved, and the jam passes the “wrinkle test” (see below “tip”). If it isn’t quite ready, cook for short intervals (no more than a couple of minutes) in order not to overdo it, and repeat the test. I find that rhubarb jam has a slightly looser texture anyway which I like, so take care not to cook the jam too much or you will lose the flavours of the fruit.

If any scum has formed on the top, simply skim this off before pouring the jam into the sterilised jars. I use a heatproof metal funnel for this.

To seal the jars, immediately place a wax paper disc on the top of the jam, with the wax side facing down. This will help prevent any mould from forming. Next, make the jars airtight by placing a cellophane jam pot cover over a damp tea towel or clean dishcloth to wet it slightly. Place these tightly over the top of the jar, and attach them firmly using elastic bands. As the cellophane dries, it will tighten and stretch over the jar, helping to keep the jam airtight.

Tip – to check whether your jam is ready, chill a plate in the freezer in advance. Once you think your jam has reached the right consistency, drop a little jam onto the plate and drag it along with your finger. If it creases up with a jam-like consistency it is ready, if not, return the mixture for a couple more minutes to the heat, before testing again.