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Whole Fruit Strawberry Jam
2 lbs. Pressed Berries 7 level cups (3 lbs.) Sugar 1 level teaspoon powdered tartaric or citric acid or Juice of 1 lemon bottle (scant 1/2 cup) CERTO Select about 2 quarts small or medium sized, fully ripe berries.
Large berries may be used for Crushed Berry Recipe below.
After hulling, weigh out 2 lbs. berries. Measure sugar into small 'separate pan. Spread about one quarter of the berries on their sides in single layer on a platter and gently press each berry to a thickness of ¼ inch with bottom CERTO of CERTO bottle. (This leaves skins nearly intact, but ruptures fruit inside and makes it hollow, allowing boiling sugar to saturate tissues quickly.) Transfer pressed berries to large kettle and cover with layer of sugar. Repeat this operation with all the berries, placing layers of pressed berries and sugar alternately in kettle, putting balance of sugar on top. Then add lemon juice, or preferably powdered tartaric or citric acid. This addition promotes & quicker set, thus keeping the fruitevenly distributed in the Jam. Let stand over night, or at least 5 hours, so that part of sugar will be dissolved and mixture can be stirred and cooked without crushing fruit. Use hottest fire and stir constantly before and while boiling. Boil hard for three minutes, remove from fire and stir in CERTO. From time jam is taken off fire allow to stand not over 5 minutes, by the clock, before pouring. In the meantime skim, and stir occasionally to cool slightly. Then pour quickly. If in open glasses paraffin at once. If in Jars seal at once and invert for 10 minutes to sterilize the tops. Crushed Strawberry Jam ▲ level cups (2 lbs.) CRUSHED Berries 7 level cups (3 lbs.) Sugar ½ bottle (scant 1/2 cup) CERTO For this jam it is necessary that each berry be broken up.
Therefore, crush about 2 quarts ripe berries in separate portions, so that each berry is mashed. This allows fruit to quickly absorb the sugar during the short boil. Measure crushed berries into large kettle, add sugar and mix well. Use hottest fire and stir constantly before and while boiling. Boil hard for one full minute, remove from fire and stir in CERTO. From time jam is taken off fire allow to stand not over 5 minutes, by the clock, before pouring. In the meantime skim, and stir occasionally to cool slightly. Then pour quickly. If in open glasses paraffin at once. If in jars seal at once and invert for 10 minutes to sterilize the tops.
A short-boil pectin jam from the era when Certo came in a glass bottle and jars were sealed with wax. The technique is sound; the sealing instructions are not, and the pectin measurement needs translating.
- The hinge: press, do not crushThe point of flattening each berry to about a quarter inch with the flat of the bottle is to rupture the interior while leaving the skin whole, so hot syrup can flood the hollow fruit in three minutes. Crush the berries and you have made the second recipe, not the first.
- Certo quantitiesThe recipe's own gloss, "½ bottle (scant 1/2 cup)", implies a bottle of about 8 fluid ounces, so the measure wanted is a little under half a cup, roughly 7 tablespoons. Modern liquid pectin comes in 3-fluid-ounce pouches (6 tablespoons), so one pouch is close but not identical, and the original figure is loose enough that exact matching is guesswork. Follow the quantity printed on whatever pectin you buy.
- The acid is not optional flavouringA teaspoon of tartaric or citric acid, or the juice of one lemon, is there to speed the set so the whole berries stay suspended rather than floating to the top of the glass. Citric acid is sold in the canning aisle; tartaric acid with winemaking supplies.
- The overnight standLayering berries with sugar and leaving them five hours or more draws out juice and partly dissolves the sugar, so the pan can be stirred without smashing the fruit. Skip it and the undissolved sugar means the mixture cannot be stirred without breaking the berries.
- Boiling times"Boil hard" means a full rolling boil that cannot be stirred down, three minutes for pressed berries and one for crushed. Stir constantly on the highest heat; a wide, heavy pan and a long-handled spoon make this manageable.
- Do not use paraffinWax seals on open glasses, and inverting filled jars to sterilise the lids, are both long abandoned. Mould grows under wax and inversion does not produce a reliable seal. Fill clean hot half-pint jars, leave 1/4 inch headspace, apply two-piece lids and process in a boiling water bath according to current canning guidance for your altitude.
- YieldTwo pounds of fruit with three pounds of sugar gives roughly nine half-pint jars. Have jars washed, hot and lined up before the pectin goes in, since the recipe allows only five minutes from pan to jar.
Certo was one of the earliest liquid fruit pectins sold to home cooks, extracted from apple pomace, and its arrival in the years around the First World War changed jam-making: instead of boiling fruit down for half an hour or more to concentrate its natural pectin, a cook could boil for one to three minutes and set the jam with an additive. The result was brighter colour, fresher flavour and more jam from the same fruit, which is one reason the pectin makers published booklets like this one, since the method had to be taught. This particular recipe is a small showpiece of that logic: because the boil is so short, the berries never disintegrate, and the bottle-pressing trick exists to let syrup penetrate whole fruit in the few minutes available.