Modding my jam safely?

February 9, 2012 12:37 PM

I want to mix slices of lemon into some jam from the store. How long will it keep in the fridge after I do this?

My plan is to wash this Meyer lemon really thoroughly, then slice it up thin and mix it into this (currently unopened) jar of blueberry jam. Once I do that, how long is it safe to keep in the fridge? My instinct says that the abundance of sugar and acid should keep things pretty safe, but I don't know whether that's true. Ideally, I'd like to keep it around for at least a month without worrying.

posted by rivenwanderer to home & garden (6 answers total)

If it's in the fridge, it should be fine, but the flavors won't really meld if the lemon's not heated with the jam.
posted by Ideefixe at 12:44 PM on February 9, 2012

It depends almost entirely on the proportion of sugar in the jam. Jam my grandparents used to make contained vast quantities of white sugar and barely needed refrigeration. You'll note that something like honey doesn't need refrigeration at all. On the other hand, many kinds of store-bought jam reduce the amount of sugar and make up for its thickening properties with gums and pectin. As a result, they spoil much more readily, even in the refrigerator. Luckily, jam "spoils" either by molding or by fermenting. Both kinds of spoilage are clearly evident, and neither one is likely to sicken you significantly, unlike something like eggs or poultry meat.
posted by Nomyte at 12:46 PM on February 9, 2012 [3 favorites]

I don't think it would make you sick if it's kept in the fridge. I also don't think it sounds like it would taste all that good. My personal plan would be heating a sugar syrup and boiling the lemon slices in that -- basically making a marmalade -- and then mixing that in.
posted by pie ninja at 1:02 PM on February 9, 2012

Well, I'm a weirdo who likes eating lemon by itself, so it sounds like mixing it in the jam should be OK for me. Thanks!
posted by rivenwanderer at 1:05 PM on February 9, 2012

The sugar will draw moisture out of the lemon, so you'll have to stir it up every time before you eat, or have drippy spots in the jam. It's also possible that the moisture from the lemon will help mold grow on the sugar from the jam, so you'll want to look at the exposed pieces of lemon before you stir it up. Sounds like a fine plan - I hope it's delicious and you eat it quickly, but you should probably have a month. Just don't eat it in the dark for a midnight snack if you haven't checked it lately.
posted by aimedwander at 1:27 PM on February 9, 2012 [2 favorites]

It should be fine, but what's your goal here?

If it's to have blueberry jam with a lemony essance I'd suggest dumping the jam into a sauce pan and grating the lemon zest into it, along with maybe a tablespoon of the lemon juice. Bring this to a low boil, dump back into the jar (don't put the lid on right away or it'll attempt to seal itself which would be a bad thing with that kind of jar and lid) and refrigerate.

If you're after something else with your conglomeration, then... weird. But enjoy!
posted by Momorama at 4:33 PM on February 9, 2012 [1 favorite]