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Pectin Stock Calculator
Calculate apple and water quantities for making homemade pectin stock.
How We Calculate This
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
Frequently Asked Questions
Pectin stock is a concentrated liquid extracted from apples (which are high in natural pectin) by simmering them in water. It is used to help low-pectin fruits (like strawberries, cherries, and rhubarb) achieve a good jam set without using commercial pectin powder.
Cooking apples like Bramleys are ideal as they are very high in pectin, especially when slightly under-ripe. Crab apples are excellent too. Eating apples contain less pectin but can still be used. The cores, peel, and pips contain the most pectin, so include them.
Good pectin stock should set slightly when cooled — test by putting a teaspoon on a cold saucer. It should have a gel-like consistency. If it remains liquid, it may need longer cooking or the apples may have been over-ripe.
Add approximately 150ml of homemade pectin stock per 1kg of low-pectin fruit. Add it to the fruit before the sugar. You may need to experiment slightly, as the pectin concentration varies depending on the apples used and how long they were cooked.
Pectin stock freezes brilliantly. Pour into ice cube trays or small containers and freeze for up to 12 months. Defrost as needed. It can also be used immediately. Fresh pectin stock keeps in the fridge for 3-4 days.
Yes! The cores, seeds, and peel contain the highest concentration of pectin. Chop the apples roughly without peeling or coring. After simmering, strain through a muslin cloth or jelly bag — do not squeeze or the stock will be cloudy.
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Last updated: February 2026
All calculations are based on standard ratios and conversions. Results may vary with specific ingredients, equipment, and conditions.