Crystals of what? Tartaric acid crystals, or is the sugar in it actually crystalizing?

If it's little glass-like slivers that melt in water, it's probably crystals of tartaric acid. These generally settle towards the bottom in juice, jelly, etc. but could be found throughout. It's harmless but annoying, since it makes jam, juice, or jelly gritty.

You need to let the juice sit for at least 24, and preferably 48, hours in the fridge BEFORE you make it into jelly -- the tartaric acid crystals will form and fall to the bottom of the pitcher/jar/container, and then you can carefully decant the juice to leave them behind.

If it is the sugar itself crystalizing (kind of the way honey will crystalize) it means you cooked it too long and removed too much of the moisture. You can put it into a container of hot water and melt it, but you'll have runny melted jelly that would only be good for pouring over ice cream. Or, if its quite solid, perhaps you could try just whipping it like crystalized honey and see what it becomes, may be edible that way.

If this happened in the refrigerator after several weeks of being opened, it means some of the liquid evaporated out of the preserve (especially on the top) leaving a higher ratio of sugar crystals behind.

It is hard to "retrieve" crystallized jam. Basically she needs to use a more airtight lid and consume the jam more quickly.

If this is a product you're selling, you might want to offer some preserves in smaller jars for those customers in small households. They may pay a premium but there will be a benefit in quality.

Carol

Thank you denninmi and Carol for your input. The jelly was put in 1/2 pint jars but the lady didn't open it up until recently. She had bought the jelly back in December. She still likes the taste and she has it refrigerated now that she has opened it and I offered to give her another jar of jelly or her money back and she said no, that this was fine, she just didn't expect the crystals. So, maybe it is a combination of things? I may have cooked it too long, or I didn't let the juice sit overnight or it sounds like some of the liquid may have evaporated and my friend needs to keep a tighter seal. Thanx so much for your input. I get a lot of valuable information from this section. We made some good money this past year making jams and jellies. People like our products and I want to make sure I produce a quality product. Thanx again.