The sour: balancing sweet and sour
Spirit, citrus and sugar, shaken hard. Learn to balance those three and you can make most of the classic cocktails on any bar menu.
Why it works
A sour is three things: a spirit, fresh citrus and something sweet. The old rule is 2:1:1, so 50 ml spirit, 25 ml citrus and 25 ml syrup. That works, but most bartenders now find it a little sweet and use less sugar than citrus: 50 ml spirit, 25 ml citrus, 20 ml syrup, or for a bigger drink 60 ml spirit with 22.5 ml each of citrus and syrup. Start with one of these, then adjust to your fruit and your taste. The shake matters as much as the spec. It chills the drink to below 0 °C, adds meltwater that softens the alcohol, and beats in air that gives a sour its light, lively texture.
Citrus is the part that changes most. Squeezed juice loses its fresh aroma within hours as the volatile oils fade and the juice oxidises, so squeeze it on the day, ideally within a few hours of serving. Lime is a slight exception: freshly squeezed, it can taste sharp and a little bitter, and many bartenders find it at its best a few hours later. By the next day both lemon and lime taste dull and flat. Bottled juice has none of the aroma and often tastes cooked. Lemon and lime are about equally acidic, roughly 6 percent acid, but lemon is almost all citric acid and tastes clean and bright, while lime carries some malic acid and has a sharper, greener bite. Lime suits rum, tequila and gin; lemon suits whisky, brandy and amaretto.
Sweetness is the other half of the balance, and it does not only come from syrup. A liqueur such as Cointreau, maraschino or amaretto is part spirit and part sweetener, so when you add one, cut the syrup. Rich 2:1 syrup is about one and a half times as sweet as 1:1, so use less. A pinch of salt, or two drops of saline solution, does not make a drink salty. It suppresses bitterness and makes citrus and sugar taste rounder. Egg white adds no flavour but changes the texture: its proteins unfold when shaken and trap air, giving a silky body and a white cap of foam. Aquafaba, the liquid from a tin of chickpeas, does the same for vegans.
From this one template comes a whole family. The Daiquiri is rum, lime and sugar; the Gimlet swaps in gin; the Whisky Sour uses bourbon and lemon, often with egg white. The Margarita and the Sidecar replace most of the syrup with orange liqueur. The Pisco Sour is Peru and Chile's national drink, with egg white and bitters. The Amaretto Sour and Tommy's Margarita, made with agave, show the template working with a sweet liqueur and with a different sugar. In Italy the same idea works well with what is already in the cupboard. Use limoncello as the sweetener in a gin sour, or make an amaro sour with Averna or Montenegro: the amaro brings both sugar and bitterness, so it needs only a little syrup and makes a fine aperitivo.
What you need
- Two-piece shaking tin: A large and a small tin seal tightly and chill fast; a three-piece cobbler shaker works too.
- Jigger with ml marks: Sours depend on 5 ml differences, so measure every time rather than free-pouring.
- Citrus press: A hand-held lever press gets more juice and less bitter peel oil than a reamer.
- Hawthorne and fine strainers: The Hawthorne holds back ice; the fine strainer catches pulp and ice shards for a clean, smooth drink.
- Good, dry ice: Plenty of hard ice from the freezer, not wet, half-melted cubes, which over-dilute.
- Dropper bottle of saline: 20 g salt dissolved in water to make 100 ml; it keeps for months.
Step by step
Chill the glass and squeeze the citrus
Put the coupe in the freezer, or fill it with ice and water while you work. Squeeze the lemons or limes and strain out the pips. A medium lemon gives about 30–40 ml, a lime about 20–30 ml.
Tip: Squeeze limes up to a few hours ahead and keep the juice covered in the fridge. Lemon juice is best within the same few hours too.
Build the cheap things first
Measure the citrus into the small tin, then the syrup or liqueur, then the spirit. If you spill or mis-measure, you lose juice and sugar rather than good spirit. Add a pinch of salt or two drops of saline now.
Add egg white and dry shake
If the drink takes egg white, add about 25 ml, which is roughly one medium egg's white, or 25 ml aquafaba. Close the tins and shake hard without ice for 10–15 seconds. With no ice to chill and thicken things, the proteins unfold and whip into foam more freely.
Tip: Drop the coiled spring from your Hawthorne strainer into the tin for the dry shake. It works like a whisk and gives a thicker foam.
Shake hard with ice
Fill the large tin about two-thirds with ice, pour the drink over it and seal. Shake hard for 10–15 seconds, until the outside of the tin is frosted and painfully cold. A short, violent shake gives the right chill, dilution and aeration.
Tip: For the thickest foam, reverse the order: shake with ice, strain into the empty tin, then shake again without ice for 10 seconds.
Taste before you pour
Dip a straw or a spoon into the tin and taste. If it makes your mouth pucker, add 5 ml syrup; if it tastes like sweets, add 5 ml citrus. Shake briefly again after any change. A good sour tastes bright first, then rounds off without a sticky finish.
Tip: Tasting from the tin, cold and diluted, is the only honest test. Room-temperature ingredients taste sweeter and boozier than the finished drink.
Strain
Empty the chilled glass. Hold the Hawthorne strainer on the tin and pour through a fine strainer into the coupe. For a drink served on the rocks, strain over fresh ice in a tumbler, never the shaking ice.
Finish and garnish
Let an egg-white sour settle for 30 seconds so the foam rises. Add three drops of Angostura bitters on the foam and drag a cocktail stick through them. For other sours, express a strip of lemon or orange peel over the top so the oil mists the surface.
Tip: The bitters are not only decoration. Their aroma is the first thing you smell, and it covers any faint eggy note.
Eight classic sours
| Drink | Spec | Glass | Garnish |
|---|
| Daiquiri | 60 ml white rum, 25 ml lime, 20 ml syrup | Coupe | Lime wheel, or nothing |
| Whisky Sour | 50 ml bourbon, 25 ml lemon, 20 ml syrup, 25 ml egg white | Tumbler over ice, or coupe | Angostura drops on the foam |
| Margarita | 50 ml blanco tequila, 25 ml lime, 20 ml Cointreau, 5 ml agave syrup (optional) | Coupe or tumbler over ice | Half salt rim, lime wedge |
| Sidecar | 50 ml cognac, 20 ml lemon, 20 ml Cointreau | Coupe | Orange twist; sugar rim optional |
| Gimlet | 60 ml gin, 20 ml lime, 20 ml syrup | Coupe | Lime wheel |
| Pisco Sour | 60 ml pisco, 30 ml lime, 20 ml syrup, 25 ml egg white | Coupe or small tumbler | Three drops of Angostura on the foam |
| Amaretto Sour | 45 ml amaretto, 20 ml bourbon, 30 ml lemon, 5 ml 2:1 syrup, 15 ml egg white | Tumbler over ice | Lemon peel and a cocktail cherry |
| Tommy's Margarita | 60 ml blanco tequila, 30 ml lime, 15 ml agave nectar | Tumbler over ice | Lime wedge |
How sweet is your sweetener?
| Sweetener | Sugar per 10 ml | Sweetness vs 1:1 syrup | Replaces 20 ml 1:1 syrup |
|---|
| 1:1 simple syrup | About 6 g | 1x | 20 ml |
| 2:1 rich syrup | About 9 g | About 1.5x | 13–15 ml |
| Honey syrup (1:1 honey and water) | About 6 g | About 1x | 20 ml |
| Agave nectar, undiluted | About 10 g | About 1.7–2x | 10–12 ml |
| Cointreau or triple sec | 2.5–4 g | About 0.4–0.6x | 35–50 ml (in practice, use 20–25 ml and a little syrup) |
| Maraschino liqueur | About 3 g | About 0.5x | About 40 ml (usually used in small amounts for flavour) |
Troubleshooting
It's too sharp and makes my mouth pucker
Your citrus is juicier or more acidic than the spec assumed, or you counted a liqueur as if it were syrup. Add 5 ml syrup and shake again. A drop of saline also softens harsh acidity without adding sugar.
It's too sweet and cloying
Usually rich syrup used at the 1:1 volume, or a sweet liqueur plus a full dose of syrup. Add 5 ml citrus, or cut the syrup next time. Remember that cold hides sweetness, so a drink that tastes balanced at room temperature will taste sharp once shaken.
It tastes thin and watery
The ice was wet or the shake was too long and gentle. Use hard, dry ice straight from the freezer and shake briefly and violently. A little more syrup, or switching to rich syrup, adds body, as does egg white.
No foam, or it collapses straight away
Fat kills foam, so check for any trace of yolk and wash oily tins. Carton whites and old eggs foam less well; use fresh eggs or a little more white. Dry shake longer, add the strainer spring, or try the reverse dry shake.
It smells eggy, a bit like a wet dog
Some eggs have a sulphury note that the foam carries straight to your nose. Use very fresh eggs and do not overdo the white; 15–25 ml is plenty. Bitters on the foam or an expressed lemon peel covers the smell.
It tastes dull and flat
The juice is too old, or the drink lacks salt. Squeeze fresh citrus the same day and add a pinch of salt or two drops of saline. Expressing a citrus peel over the top adds the fresh aroma back.
Raw egg and alcohol
Raw egg white carries a small risk of salmonella. Use very fresh eggs from a trusted source, kept cold, or pasteurised liquid egg white.
- Avoid raw egg drinks for pregnant women, young children, older people and anyone with a weakened immune system; use aquafaba instead.
- Crack eggs into a separate cup first, so a bad egg or a broken yolk does not spoil the drink.
- Egg and chickpeas are both allergens; tell guests what is in the foam.
- A sour holds 50–60 ml of spirit and tastes gentle. Count it as a strong drink, offer water alongside, and never drink if pregnant or driving.
