In a shop lime often gets called a green lemon. The two are different species, and they do not stand in for each other in the kitchen.
What separates lime from lemon?
Both are citrus, and they belong to different species.
Lemon is Citrus limon; lime is Citrus aurantiifolia or Citrus latifolia.
Lime is smaller, its skin is thinner and its colour stays greenish even when ripe.
Its acid load runs slightly above lemon, with a pH between 2.0 and 2.4.
The aroma profile differs entirely; lemon is floral while lime is resinous and faintly bitter.
| Measure | Lime | Lemon |
|---|---|---|
| pH | 2.0-2.4 | 2.2-2.6 |
| Vitamin C (100 g) | 29 mg | 53 mg |
| Skin thickness | Thin | Thick |
| Aroma | Resinous, sharp | Floral, rounded |
| Juice per fruit | 25-35 ml | 40-60 ml |
Which varieties of lime exist?
Two main varieties are common.
Persian lime is the one most widely traded: large, seedless and moderately acidic.
Key lime is smaller, carries seeds and has a far more intense aroma.
Key lime gives its name to the pie, and substituting Persian lime changes the result.
Persian lime is the common one in Turkey and usually the one on the shelf.
Where is the aroma of a lime stored?
In lime, as in lemon, most of the aroma sits in the peel.
The oil sacs in the skin carry limonene and citral.
In the juice the acid dominates and aroma comes second.
So using only the juice in a recipe leaves half the aroma behind.
Adding grated zest changes a recipe noticeably.
How does lime zest get used?
Only the outer green layer gets grated.
The white pith, the albedo, carries a bitter taste.
The grate needs to be fine; a coarse grate leaves fibrous pieces in a dish.
Zesting happens before juicing; a squeezed fruit is hard to grate.
The zest goes in immediately; grated zest left standing loses its aroma quickly.
How does dried lime get used?
Two forms exist: slices and whole fruit.
Slices go into drinks, dropped into hot or cold water.
Whole dried lime goes into dishes in Middle Eastern cooking, common in Iranian and Gulf kitchens.
In the whole form the fruit gets pierced and dropped into the pot, releasing acid and aroma through the cooking.
Drying darkens the fruit and shifts the aroma in a resinous direction.
How does it work in drinks?
Cocktails are the most common use; mojito, margarita and gimlet all build on lime.
Limeade takes the place of lemonade; with sharper acid the sugar rises a little.
Slices go into soda and sparkling water.
It appears in iced tea.
A dried slice sits on the rim of a glass, holding its shape far longer than a fresh one.
Where does it belong in cooking?
It is a base ingredient in Mexican and Southeast Asian cooking.
It replaces lemon with seafood; its sharper acid cuts the fat of the fish better.
In avocado dishes such as guacamole it works as both acid and a guard against browning.
In spiced dishes it balances the heat, a use common in Thai and Vietnamese cooking.
It goes into marinades; acid denatures the proteins in meat and softens the texture.
Can it replace lemon?
By quantity yes; by aroma no.
Lime juice can replace lemon juice measure for measure in a recipe.
The result tastes different, though; lime is sharper and less floral.
In desserts that difference is pronounced; a lemon cake and a lime cake are not the same product.
In dressings and marinades the difference causes less trouble.
What is the nutritional value of lime?
A hundred grams carries 30 kilocalories.
Vitamin C comes to 29 milligrams, below lemon but still a notable source.
Fibre runs 2.8 grams.
Carbohydrate sits at 10.5 grams.
One medium lime weighs about sixty grams and gives 25 to 35 millilitres of juice.
Does a dried lime slice carry any nutrition?
A hundred grams carries 280 to 320 kilocalories, mostly concentrated sugar and fibre.
In practice those numbers say little; the product never gets eaten by weight.
A single slice weighs some three grams, and what reaches the drink is negligible.
Vitamin C largely disappears during drying, and oven drying costs the most.
Freeze-drying preserves it well, though that method rarely gets used for dried slices.
How does fresh lime get chosen?
Fruit that feels heavy for its size carries more juice.
The skin should look bright and taut; a wrinkled skin shows the fruit has lost water.
Fruit that is entirely dark green may be unripe; tones leaning slightly yellow carry more aroma.
Fruit that feels hard and woody has dried out.
Waxed fruit does not suit any recipe using the zest.
How does lime get stored?
Fresh lime keeps two or three weeks in a fridge.
At room temperature it keeps a week, losing water over that time.
The zest can be grated and frozen, keeping six months in small portions.
The juice freezes in an ice cube tray, which makes measured use in recipes easy.
Dried slices keep six to twelve months in an airtight jar somewhere cool and dark.
How does lime juice come out?
The fruit gets rolled under the palm on the bench first, which breaks the sacs inside and frees the juice.
Fruit at room temperature gives more; a lime from the fridge waits ten minutes.
It gets cut across rather than lengthwise; cut lengthwise it yields less.
A squeezer gets used; squeezing by hand leaves half the juice in the fruit.
Where seeds are present the juice passes through a sieve.
In which recipes does lime not replace lemon?
Lemon cake and lemon tart; the floral aroma of lemon sits at the centre of those recipes.
Soups finished with egg and lemon, where lemon juice is the classic component and lime tastes different.
Olive oil vegetable dishes, where lemon is the traditional pairing.
For grilled fish either works, and the difference becomes a preference.
In cocktails the reverse holds; where a recipe calls for lime, lemon does not give the same result.
