Lakeland is a good store. Pricey, but good quality and they have excellent customer service and guarantee their products for, I think, three years. They sell actual canning jars (made for heat processing, in either a boiling water bath or a pressure canner) and other jars with screw-on lids. Those other jars should be fine for refrigerator preservation, but all the reading I've done indicates using paraffin paper seals and screw-on tops instead of sanitizing the filled jars by heat processing leaves you at risk of botulism. Not something I'd want to deal with, considering that just a hint of the botulism toxin will land you in ICU! Not worth the risk, in my eyes.
https://food.unl.edu/canninghttps://nchfp.uga.edu/questions/FAQ_canning.htmlI think that if you didn't fill those non-canning Lakeland jars all the way so that there was room for content expansion you might be able to freeze them. Not really sure, though. If you have freezer space you might try one jar that way to see if it breaks. If not, you could always freeze instead of heat-preserving.
I found Kilner preserving jars (1/2 litre size) at 2 pounds each on Sainsbury's website, but it was almost impossible to get them to deliver any! I had a grocery order that included 12 and they brought the groceries and 8. I ordered two dozen two other times and they never showed up. The first time they didn't bother to let me know they were not coming. The second time they sent me an email the day after the delivery was supposed to happen that they were not coming! (So much for shopping at Sainsburys ever again. And I had followed their directions about placing a bulk order, in advance.) But their price was by far the best price I've found so far. In the States I could get 12 jars for the equivalent of about 8 pounds, so it stung to pay UK prices - especially as I'd left dozens completely unused, still-wrapped jars behind when we moved over.
Fortunately, I only have to pay that one time, as the jars are completely re-usable. We are going to a hobby shop tomorrow that has the little Ball quilted glass jelly jars at 1/2 of what I paid for some on Amazon, and I'm hoping they have larger jars at as good prices.
Tip - for acidic foods like tomatoes or jams made with high-acid berries, or pretty much anything with a good dose of vinegar in it you can do the heat preservation in a big pot. You just need to be sure that there's a rack in the bottom so that the jars are not in direct contact with the bottom of the pot, and that there's an inch of water over the tops of the jars. You start timing from the start of the boil. I just canned dill pickles and the recipe stated a 15 minute boiling water bath. So they should remain safe indefinitely, although I understand the quality starts to deteriorate after about a year. Things like meats and veg take much longer and really do need a pressure canner.
I bought white meat chicken from Tesco at about 2 pounds a package (it looks like it came from the wings, but is boneless and decent quality) and am going to be canning it later today. To do that I fry it (with salt and pepper) in my cast-iron pan until it's browned and about 2/3rds of the way done. Then I pack it into jars and pour boiling-hot chicken broth over it until the jar is pretty much full. (You want to leave about an inch of "head space" between the level of the broth and the lid, for expansion.) Then I'll be processing it in the pressure canner for about one hour fifteen minutes.
It comes out nice, and when I want to make, say, chicken soup or some other dish that contains chicken I can just pull it off the shelf and add it to what I'm making. (It will be fully cooked by the time the processing is over.) Or I can just microwave it to warm it up and serve it. Saves a lot of time. And it has the added bonus of being available to eat "as is" if the power goes out for an extended period of time. I have heard that you can add all sorts of other spices to the jars, if you're going to purpose the chicken for use in specific dishes. But I just keep it basically plain. The salt and pepper I put in are not required, and you can use boiling water instead of the broth in there as well. And you don't have to brown the chicken - it just needs to be cooked about 2/3rds of the way before adding it to the jars, so if you wanted to boil/bake/steam it without browning it you certainly could. And if you're going to use a hot water bath or a pressure canner, it is not necessary to sterilize the jars ahead of time. They should be sparkling clean, but the processing temps are high enough to kill any bacteria, fungus, or mold spores that might be on them beforehand.
Oh, and if you go the Kilner route, check the lids. I have had three lids out of twelve where the sealant around the lid was not evenly applied, and it interfered with proper sealing of the jar after it came out of the kettle. If you can get "Ball" lids, they seem to be of better quality. I brought over quite a few of the generic Walmart ones and they also seem a bit better - I've never had a problem with them sealing up. Have not checked ASDA to see if they carry anything like that - but am hopeful, as they are owned by Walmart. (I think.)
Trivia: you may see reference to canning jars as "Mason" jars. That's not the name of a company, it's a method of creating the glass. It's sturdier than regular bottle glass, to withstand the heat and pressure in a canner. So Ball and Kerr jars (in the USA) are Mason jars. I'm assuming that Kilner jars probably are, as they are a thicker glass. I'm not sure about the Leifheit (I think so), or Weck (no idea).
