Guava Paste That Slices, Not Guava Jam That Runs

Three stages

1. Prep — cut the blossom end, sieve the seeds

   Top and tail the fruit, cut out any brown or soft patches and quarter them. Guava seeds are small, hard and numerous, and the only way to remove them is to simmer the fruit for 20 minutes and push it through a nylon sieve or a food mill on the fine screen.

   Guava has a hard seed core and a soft outer layer, so cut every fruit down the middle and check it before you commit: a fruit with brown, mushy core has already started to ferment and will give the paste a fermented edge that no amount of sugar hides.

2. Cook — 75 minutes, and it will spit

   Add the sugar to the strained pulp with the lime juice and the cinnamon if you are using it, and cook over low heat for 60-75 minutes, stirring every few minutes with a long-handled spoon. As the paste thickens it spits like lava, and a 78 Brix paste will take the skin off your forearm; wear long sleeves and keep your hand out of the pan.

   The paste is ready when a spoon drawn across the base leaves a clean channel that fills in slowly, and a chilled sample holds a sharp cut. It should read about 78 Brix or 108 °C — roughly ten degrees hotter than a jam, because the sugar concentration is far higher. Stir constantly for the last ten minutes, because this is the point where it goes from stirring easily to scorching in seconds.

3. Seal — pour into moulds for blocks, jars for paste

   For a block, line a 15 x 10 cm tin with baking paper, pour the paste in and leave it at room temperature for 24 hours. It sets to a firm, sliceable block that keeps for months wrapped in paper in a cool cupboard — no water bath and no vacuum needed, because 78 Brix is not a medium anything can grow in.

   For jars, pour into warm 250 ml jars at 90 °C, cap and invert for 5 minutes to sterilise the headspace, then turn upright. Once opened, a jar of guava paste will keep for six months in the fridge if you always cut it with a clean, dry knife.

Failure diagnosis

Four things go wrong with this preserve more often than anything else. Open the one you are looking at.

• Will not set

  Guava paste does not fail to set — it fails to stop. If yours is too stiff to spread after two days, you simply took it too far; melt it with 50 ml water over low heat and re-mould it.

• Graining and crystals

  Low risk despite the 900 g sugar ratio, because guava is acidic and the long cook inverts a good part of the sucrose. Cut the paste at 78 Brix and no higher; past 80, crystals appear on the surface within weeks.

• Mould or spoilage

  A 78 Brix paste is shelf-stable; the only mould risk is on the cut face of an opened block. Keep the block wrapped, cut with a dry knife, and press a piece of baking paper against the cut face.

• Colour loss

  Pink guava paste goes from coral to brick red over a year and then holds. This is the most forgiving preserve in the book and the one to make if you want to give away something that will still be good next winter.

On the same shelf

Other tropical recipes, all already published.