There's an old song that goes like this: "Lemon tree very pretty, and the lemon flower is sweet, but the fruit of the poor lemon is impossible to eat." Now, you know that just isn't true. Lemons are, in fact, a very popular fruit used in a great variety of recipes. But, perhaps you don't have that pretty lemon tree in your own backyard. When a recipe calls for lemons and all you have on hand is lemon juice, can you use that instead?
The Parts of a Lemon
Two main parts of a lemon are used in recipes: its juice and its zest. Squeeze the fruit, remove the seeds, either strain out the pulp or leave it in, and there you are — you've got your juice. Simple.
The zest is a bit more complicated; it consists of the very outer layer of the lemon that's bright yellow in color. Normally, zest is obtained by grating or paring the lemon (or using a special tool called, naturally, a "zester"), carefully making sure that the yellow peel only is removed — not the white pith directly under it, which is fibrous and bitter.
Of the two components, a substitute for lemon juice is required more often than is a substitute for zest.
Fresh Lemon Juice vs. Bottled Conversion
The first thing that comes to mind when contemplating a fresh lemon juice alternative is undoubtedly the bottled stuff that can usually be found in the back of the refrigerator — that emergency supply of lemon juice that seemingly lasts forever. Bottled lemon juice that contains preservatives and other additives does have a long life, but the same elements that keep it safe in the fridge for up to 18 months are also what keep it tasting a lot less fresh than freshly squeezed juice. It's more sour than tart, and it has a lingering chemical aftertaste that's quite unpleasant for many people.
Some recipes call for the juice of one lemon, rather than a standard measure. So bear in mind that the average medium-size lemon contains 2‒3 tablespoons of juice and measure accordingly (use the same amount of bottled juice as you would if using fresh).
However, bottled preserved lemon juice can be used successfully in many recipes. As a general rule, the less fresh juice called for — or the smaller the proportion of juice in the recipe — the better the result will be. If the finished dish is intended to be sour, bottled juice may blend in quite well. Also, bottled juice in cooked dishes that call for fresh juice can work out fine, as opposed to raw dishes that often depend on the bright taste of fresh juice.
You can have real lemon juice available whenever you want it! Just pour about 2 tablespoons of fresh juice into each of the compartments of an ice cube tray. Freeze; then put the cubes into a tightly sealed freezer bag. Lemon juice will last for several months in the freezer.
Bottled organic lemon juice is another alternative to freshly squeezed lemons. Without additional preservatives, organic juice has a taste closer to that of fresh juice. However, it doesn't last as long in the fridge — about two weeks maximum.
Replacing Lemon Zest With Lemon Juice
Lemon zest, the small scrapings from the outer yellow layer of the lemon, is sometimes included as a recipe ingredient. Although lemon zest has a flavor quite different from lemon juice (more flowery, less sour), juice can act as an acceptable substitute in many cases.
Replacing zest with juice works best when only a small amount of zest is called for. The conversion ratio is flexible; 2‒3 tablespoons of juice may replace anywhere from a teaspoon to a tablespoon of zest. Start with just a little juice and keep tasting till the flavor is where you want it to be.
If the recipe relies on the zest to add a conspicuously bright, fresh note, it might be better to replace the zest with lemon extract or even lemon marmalade instead of juice; add a tiny bit at a time, tasting all the way. Or, you may even decide to put off making that particular recipe on that particular day, giving yourself time for a trip to the supermarket in search of actual lemons.