Blueberry varieties - Blueberry Jam

If you want to plant some blueberries to ensure you always have fruit for making jams, you'll probably want several different varieties. Planting multiple varieties of blueberries ensures maximum yield per bush (because they cross-pollinate one another) and will allow you to choose bushes that ripen at different times, giving you berries throughout the summer.

Of the early-ripening varieties, jams made from the DUKE, O'Neal, and Climax varieties have been repeatedly ranked as top choices by consumers. These all produce high quantities of sweet berries, excellent for freezing or making jams. Through the middle of harvest, we recommend the Bluecrop, Northland, and Brightwelll. Suitable late-ripening plants include the Jersey and the Legacy. Be sure to check a USDA climatic zone map to ensure your choices will be hardy where you live.

Is Your Jam too Runny?
Many attempts at making blueberry jam end up with a very watery product, more a syrup than jam. The fault does not lie with the recipe, nor should we lay blame at the cook's feet. Unlike apples, grapes, plums, and many other fruits, blueberries are very low in pectin, and thus more likely not to jell when they ought.

If you follow your recipe closely, but your recipe for blueberry jam keeps turning out too thin, you might substitute apples or grapes for about one-third of the blueberries called for by the recipe. The high pectin content of the apples and grapes will help firm up your jam, but the relatively mild taste and color will still allow the flavor of the blueberries to shine through.

If you don't like the idea of mixing fruits in your preserves, you might add under-ripe blueberries to the recipe. As fruit ripens, it loses pectin; adding under-ripe fruit to your recipe allows you to increase the pectin without substituting in other fruits. What amount of blueberries called for in your recipe, ensure one-quarter of them are under-ripe. The flavor of the jam won't be compromised, but the jelly will be much stiffer.

This information is available as a PDF file, including a recipe for marmalade and suggestions for further reading.