Loquats are those little yellow fruits that are shaped like a kumquat, but have 2-5 large seeds in the middle. They are lightly sweet, and the trees produce the fruits in amounts that put other trees to shame. As great a snack as they are, they make a terrific jam! The flesh is similar to a soft pear in texture, and as such makes something more akin to a fruit butter than the traditional idea of a jam. A fruit butter is a thick sauce - think apple sauce but thicker and spreadable.
While we do indeed can our loquat butter, there is no FDA approved method for doing it. Because it behaves in a very similar way to apples, we decided to treat it that way and process in a boiling water canner for 15 minutes. We have never had an issue with a jar going bad, tasting funny, losing a seal or changing color. With that said, use common sense and don't treat my blog as the end-all-be-all resource for canning. Do your own homework. If you are unsure whether a fruit is high acid, buy some litmus strips and test a small amount. It will be worth the peace of mind.
Prep a boiling water canner with enough clean jars for the fruit you have, and bring it to a simmer with the jars to sterilize them.
To prep the fruit:
The amount of loquats it takes to make a pint of jam varies, but when all is said and done, allow 3/4-1 cup of sugar to every cup of cut up fruit.
Wash the loquats very well in cold water, then remembering what cut apples do in open air, you want to have a bowl of lemon water handy to keep the flesh from turning brown. Using a pairing knife, cut the loquats in half lengthwise, running the knife around like you would an avocado. The seeds are very large, and POISONOUS. Do not allow any of the seeds to remain with the flesh. They contain arsenic, so you really don't want to cook them in the jam. I'm honestly not sure how much is in there, but like apple seeds and other fruit seeds containing toxins, it's better to not eat them.
Once you have the fruit cleaned and pitted, measure it into a stock pot and add sugar for the amount of fruit you measured, also add 2 tbs of lemon juice per quart of fruit - this will help the loquat butter thicken and bring the acid level of the loquats up a bit. Work in smaller batches, only a quart or two of fruit at a time because it will be easier to get the loquat butter thicken up.
Stir everything together well over high heat until the fruit softens a bit, turn off the head and you have two choices: you can run it through the blender to puree the chucks a bit, or use a stick blender. If you choose the blender method, put the lid on all the way!! This stuff is like molton lava, and unless you work again, in even smaller batches in the blender and lid it tightly, it will spray your kitchen and you.
Once the butter is pureed mostly, bring it back up to high heat at a rapid boil until it is thick enough that it mounds up on a spoon. Again - think super thick spreadable apple sauce and you have a fruit butter.
After you have a loquat butter you are happy with, place it in the jars, leaving 1/4 inch between the top of the jar and the loquat butter. Heat the canning lids for 30 seconds to soften the sealing compound(don't boil them!!), wipe the top of each jar carefully to ensure that there is no fruit between the jar and the lid. Place the lid on the jar and screw the ring down finger-tight. Don't over do this part because you want the air to be able to escape from the jar, creating a vacuum. This is part of what keeps the fruit butter preserved!
Carefully place the jars in the water bath, and bring it up to a boil. Process at a full rolling boil for 15 minutes, and the time starts when the water comes to a full rolling boil, not a moment before. After the processing time is up, turn off the heat and allow the water to cool just a little before taking out the jars. Place them on a towel on the counter, no thermal shock is wanted here - it's a mess!
Leave your jars of loquat butter on the counter overnight - do not mess with them until then because you can disturb the seal that is forming. To check the seal, remove the ring and lift up with your finger - if it doesn't come off, and the center of the lid has sunk down a little then you have a good seal.