Triple Sec vs Cointreau vs Curacao

They sit together on the shelf, they are all orange, and recipes use the names more or less at random. They are not the same bottle, and in a three-ingredient drink the difference is most of the drink.

The short version

• Curacao is the original: orange peel steeped in spirit and sweetened, usually with a brandy or neutral base. Typically 20 to 40% ABV, and it comes in colours because of food dye, not flavour.
• Triple sec is a drier style of curacao made on a neutral base. The name means roughly "triple dry". At the cheap end it is 15 to 20% ABV and mostly sugar.
• Cointreau is a specific brand of triple sec, bottled at 40% ABV, made from sweet and bitter orange peels. It is the one most classic recipes assume even when they say triple sec.
• Grand Marnier is not in this family. It is cognac-based, sweeter, heavier and darker, and it changes a drink rather than filling a slot in one.

Why the strength matters more than the flavour

A 15% triple sec and a 40% Cointreau are not the same ingredient at different quality levels. They are different amounts of alcohol, sugar and water in the same volume, and the cheap one is mostly the last two.

Take a Margarita: 50 ml tequila, 25 ml orange liqueur, 25 ml lime. Swap Cointreau for a well triple sec and you have removed about 6 ml of alcohol and added a comparable amount of sugar and water to a drink that is 100 ml before ice. It comes out sweeter, shorter and noticeably flabbier, and no amount of good tequila fixes it.

The same arithmetic runs through the whole family of drinks built on this bottle: the Sidecar, the Cosmopolitan, the White Lady and Corpse Reviver #2 are one shape with the base spirit swapped, and in all of them the liqueur is the sweetener.

Which to buy

One bottle of Cointreau, or a good dry curacao at a similar strength. It is the single most-called-for modifier in cocktails, it lasts effectively forever at 40% ABV, and it is the difference between a home Margarita and a good one.

Blue curacao is the same liqueur with colouring. If a recipe calls for it, it is calling for the colour, and you can substitute clear curacao without changing anything you taste.

Substituting between them

If you have the cheap bottle and the recipe wants the good one, correct in two places rather than one: use a little more of it to reach the same orange flavour, and cut the other sweetener if the drink has one. If the recipe has no other sweetener, as the Margarita and the Sidecar do not, then accept that the drink will be sweeter and consider adding 5 ml more citrus.

Going the other way, if a recipe was written for cheap triple sec and you pour Cointreau, the drink will come out drier and stronger. That is usually an improvement, but it is a change.

A note on the ratio

The classic Margarita is 2:1:1, tequila to orange liqueur to lime. That is a starting point rather than a law and it was written for the strong liqueur. If you find it sharp, the fix is a barspoon of agave syrup rather than more liqueur, because more liqueur makes it sweeter and stronger and you will lose the tequila.

Everything in the Cointreau and triple sec categories rests on this bottle, and it is worth owning the good one before almost any second spirit.