Why won't my lemon juice ice cubes freeze?

May 27, 2013 3:54 PM

We were given far more lemons than we can reasonably use before they spoil. We'd like to freeze the juice from some of them to use in our later lemon-less life. However, the last time we tried freezing lemon juice, the juice never quite froze; the outside of the cube was slightly slimy and the cubes slowly oozed over a period of a few weeks into gelatinous lemon-flavored messes of glop. Since the other items in our freezer are so solid as to cause injury if dropped on one's bare foot (NOT THAT I'VE DONE THIS), it would seem to me that the temperature of our freezer is cold enough. But maybe I'm wrong! Any tips, O Hivemind?
posted by rednikki to Food & Drink (16 answers total)

I would freeze them whole, you have the zest too then and as freezing will break down the cells they should produce more juice.
posted by BenPens at 3:58 PM on May 27, 2013 [1 favorite]

Best answer: The freezing point of lemon juice is substantially lower than that of water. There's probably nothing wrong with your freezer, it just isn't made for that duty. Freezing them whole might work. Or preserving them in salt (to take a different approach entirely).
posted by janell at 4:01 PM on May 27, 2013 [2 favorites]

Well, that's how orange concentrate is no matter how cold you freeze it, so I would assume lemon would be similar.

You could try diluting it with some water.

Good luck.
posted by cjorgensen at 4:01 PM on May 27, 2013 [4 favorites]

Oh, also canning the juice would be super easy too.
posted by janell at 4:02 PM on May 27, 2013

My lemon cubes stay a bit slimy on the outside but don't ooze together. Might depend on the sugar content.
posted by Lame_username at 4:03 PM on May 27, 2013

Two things happen:

1- the dissolved citric acid and sugar in the juice lower the freezing point of the solution. I don't know to what temperature, but probably not by too much. However, many people keep their freezers not much below 32 deg F, when it should really be closer to 0 deg F. So that might be something to test for.

2- Freezer burn. Which is the molecules of the water sublimating out of the frozen mixture. Over time, this concentrates the non-water components of the lemon juice, to the point that it may not want to freeze at all.

3- The water also wants to freeze into large crystals. This is why slushie and soft serve machines need to constantly be in motion- to break up the large crystals into small ones, creating an emulsion of non-frozen juice and tiny ice crystals.

Your best bet would be to stir it while freezing it so that you get a mostly homogenous mixture, and then seal the cubes as airtight as possible. Like frozen concentrated orange juice- there is no atmosphere in the tube for the water to sublimate into, so it doesn't.

If you head to GFS, or some other restaurant supply house, you will probably be able to find little 1 or 2 ounce containers with lids that you can use for this purpose.
posted by gjc at 4:15 PM on May 27, 2013

I buy 100 percent organic lemon juice in a bottle. It lasts a really long time. Six months to a year. In fact, I've never had to throw a bottle out and there is no best before date on it. Could you not just bottle it and put it in the fridge?
posted by dobbs at 4:16 PM on May 27, 2013

I consider this a plus, lemon-juice-freezing-wise. I put it in a zip-lock freezer bag, lay it on a flat surface to freeze initially, and then smash it and there's always the right size of frozen lemon to grab.
posted by kmennie at 4:46 PM on May 27, 2013 [3 favorites]

Think about popsicles- they're not rock-hard either.
posted by showbiz_liz at 5:21 PM on May 27, 2013

I would recommend canning instead. I've used the instructions from pickyourown.org in the past, and been pleased with the results (though not for lemons; I did apple butter)
posted by contrarian at 5:34 PM on May 27, 2013

I buy 100 percent organic lemon juice in a bottle. It lasts a really long time. Six months to a year. In fact, I've never had to throw a bottle out and there is no best before date on it. Could you not just bottle it and put it in the fridge?

I would bet that fresh lemon juice wouldn't last nearly as long. Plus, old lemon juice picks up flavors and oxidizes to taste not nearly as good as it did when fresh.
posted by gjc at 7:34 PM on May 27, 2013 [1 favorite]

Ooozy lemon juice ice-cubes are pretty much what I'd expect in a domestic freezer.

For what it is worth, we freeze lemons whole. The main downside is that when thawed the skins release far more lemon oil than usual, which can be a problem if you decided you needed some lemon zest, or when you need the juice but not so much of the oil. The solution so far has been to zest them first.
posted by Good Brain at 7:40 PM on May 27, 2013

I do what kmennie does. Then all those frozen slabs of lemon juice store really nicely vertically slotted between other piles of stuff. I freeze in thin slabs so I can just snap off what I need as I go, rather than smashing all at once. Works with tomato paste, too!
posted by looli at 8:16 PM on May 27, 2013

Zest them first, use the peels to make limoncello, then, providing you have space in your freezer, freeze the peeled lemons whole.
posted by progosk at 11:21 PM on May 27, 2013 [1 favorite]

It's probably a bit late now, but if I have excess lemons I normally cut them into slices or quarters and freeze those in a bag. Then you can still thaw them out to juice or zest them, or use them as they come out of the freezer in drinks.
posted by lizabeth at 4:24 AM on May 28, 2013

lizabeth beat me to it. Slice, then freeze. Perfect dropped straight into a G&T.
posted by penguin pie at 12:20 PM on May 28, 2013