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Use of Sugar in Canning Fruit
Sugar is used in canning fruit for the purpose of improving flavor and is not necessary for preservation.
Thin Syrup--1 part sugar to 2 parts water.
Medium Syrup--1 part sugar to 1 part water.
Thick Syrup--2 parts sugar to 1 part water.
To make syrup add the sugar to the boiling water. Stir until all the sugar is dissolved, then boil 2 or 3 minutes.
Thin Syrup may be used with sweet fruits.
Medium Syrup for berries and fruits of medium sweetness. Thick Syrup for sour fruits.
A short reference entry rather than a dish, but it does tell you how to make something: the sugar syrup that goes into jars of canned fruit. The ratios still work; what has changed is everything around them.
- The point the book gets rightSugar is for flavor, color and texture, not safety. It does not make fruit shelf-stable. Preservation comes from acidity plus a correct heat process, and fruit canned in plain water or juice keeps just as well, if softer and paler.
- What this page does not tell youThere is no processing method here — no jar preparation, no boiling-water bath, no times. Use these ratios alongside a current tested process from a source such as the USDA Complete Guide to Home Canning, which gives times by fruit, jar size and altitude.
- Parts by volumeThe ratios are volumetric, as was standard. Thin is 1 cup sugar to 2 cups water, medium 1 cup to 1 cup, thick 2 cups to 1 cup. Modern charts run lighter across the board; the medium here is at least as strong as what current guides call heavy.
- The two-minute boilBoil only long enough to clarify and dissolve, as directed. Extended boiling concentrates the syrup and shifts it a grade stronger than intended, and with acidic fruit juices in the pot it can begin to invert.
- Keep it hotSyrup should go into the jars at or near boiling. Warm syrup on cold fruit in a cold jar drags out the time the contents take to reach process temperature, which is what the published times assume.
- Choosing a strengthThe book's rule still holds — thin for sweet fruit, thick for sour — but heavy syrup floats fruit and dulls it. Current guides lean towards thin syrup or unsweetened apple or white grape juice even for tart plums and sour cherries, with sweetening added at the table instead.
- SubstitutionsUp to about half the sugar can be replaced with light corn syrup or mild honey without affecting the process; honey in particular will colour and flavour the fruit. Artificial sweeteners are better added at serving than in the jar, since some lose sweetness or turn bitter under heat and long storage.
The syrup table — three named strengths, expressed as parts rather than cups so they scaled to whatever quantity of fruit came in from the orchard — is the kind of small standardization that home-canning literature of the period settled into. The flat statement that sugar is not necessary for preservation is worth noticing, because it ran against long habit — in the older preserving tradition, sugar in heavy proportion genuinely was the preservative, which is why nineteenth-century preserves call for a pound of sugar to a pound of fruit. Heat processing in sealed jars made that unnecessary, and American home-canning literature pushed hard on the idea that fruit could be put up with little sugar or none during the sugar conservation campaigns of the First World War. The New Royal Cook Book was issued by the makers of Royal Baking Powder, part of a long practice of manufacturers distributing free cookbooks that mixed genuinely useful reference material with promotion of their own product.