Pectin Stock Calculator

This calculator uses the standard UK method for homemade pectin stock. Chop the apples roughly (keeping cores, peel and pips), just cover with water, simmer until soft and mushy, then strain to extract the pectin-rich liquid. The traditional method then boils the strained liquid down — often by half — to concentrate the pectin, so treat the estimated yield as approximate.

Standard Ratios

Every apple type uses the same just-cover-with-water ratio of about 1 litre per 1kg of apples — the water is there to cover the fruit, not to control pectin. The difference between apples shows up in the strength of the stock (the yield), not the water.

• Cooking apples (Bramleys): very high pectin — 1kg apples + ~1L water, 45 min simmer
• Crab apples: very high pectin and acid — 1kg apples + ~1L water, 50-60 min simmer
• Eating apples: lower pectin (weaker stock) — 1kg apples + ~1L water, 40-45 min simmer

Yield and Usage

• Estimated yield: approximately 50-60% of the water added (indicative — homemade pectin strength varies widely, and reducing the strained liquid lowers the volume while concentrating the pectin)
• Usage: ~150ml per 1kg of low-pectin fruit
• Strain through muslin or a jelly bag — do not squeeze, or the stock turns cloudy