White Peach Jam: Blanch, Peel, and Work Fast

Three stages

1. Prep — ten seconds in boiling water, straight into ice

   Score a shallow cross in the base of each peach, lower them into boiling water for 10 seconds and move them straight into iced water. The skin should slide off in sheets under your fingers; if it tears and clings, the fruit was underripe and you should peel it with a knife and add an extra tablespoon of lemon juice to make up for the acid it never developed.

   Halve, stone and cut into 15 mm wedges. Weigh the peeled fruit and adjust the sugar to 700 g per kilo — a peach loses 12 to 18 percent of its weight in peeling and stoning, and a recipe written for whole fruit will come out oversweet.

2. Cook — acid and glucose both go in at the start

   Add the sugar, glucose syrup, lemon juice and citric acid to the fruit and bring it slowly to a boil, stirring until every grain is dissolved. Both additions matter here: the acid brings the pH down to a workable 3.4, and the glucose interferes with sucrose crystallisation, which is a real risk in a low-acid, high-sugar fruit like white peach.

   Boil hard to 105 °C — peach needs a degree more than most jam because its gel is weak — then sprinkle in the pectin blend, wait 30 seconds and boil 60 seconds. Skim, test on a frozen plate, and pot the moment the sample wrinkles.

3. Seal — 200 ml jars and a 12-month horizon

   Pot at 90 °C into 200 ml jars with a 6 mm headspace and process for 10 minutes in a boiling water bath. White peach jam is the shortest-lived preserve in the collection: at 64 Brix with a pH of only 3.4 it has less protection than anything else here.

   Date every lid and plan to finish the batch within a year. Past 12 months the peel-derived aroma is gone and the jam tastes simply of sugar and lemon, which is a waste of a fruit that is only in season for five weeks.

Failure diagnosis

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

• Will not set

  White peach is low in both pectin and acid, so a set depends entirely on the pectin and citric acid being measured properly. If the jam is still liquid at 105 °C, add 1 tsp pectin and 0.25 tsp citric acid, boil 60 seconds, and stop.

• Graining and crystals

  The highest risk in the collection and the reason the glucose syrup is not optional. A batch made without it grains within six to nine months; with it, expect two years of clean syrup. Glucose is 15 percent of the sugar here, which is the practical ceiling before the jam starts tasting of it.

• Mould or spoilage

  Low-acid jam plus a headspace above 8 mm is the classic mould combination. Fill to 6 mm, tap the jar, top up, and never reuse a lid whose sealing compound has a dent in it.

• Colour loss

  The pale cream colour goes to a honey amber within a year, and it is the one thing you cannot slow down much. Use it as a sign: while a jar is still pale, the peach aroma is still there.

On the same shelf

Other stone fruit recipes, all already published.