If you want to know how to make a guillermo, the short answer is refreshingly simple: place a couple of fresh lime slices in a small glass or cup, pull one or two shots of espresso directly over the lime, and drink it as is, or add a small splash of milk and pour it over ice. The hot espresso draws out the lime's bright citrus oils, giving you a punchy, tangy coffee-and-lime drink that lands as a small, sharp pick-me-up.
It is one of those quietly clever espresso drinks that sounds odd on paper and makes perfect sense in the cup. Below you will find a full guillermo coffee recipe, the equipment you need, ordered steps, and the handful of variations worth knowing.
What is a guillermo?
A guillermo is a lesser-known espresso-and-lime drink: hot espresso poured over fresh lime slices, sometimes finished with a small splash of milk and served over ice. It surfaces here and there on cafe menus across Latin America and, more recently, in parts of Australia, where a short, characterful coffee is part of the daily rhythm. It has never been a headline drink the way a flat white or cortado has, which is part of its charm; it tends to be an off-menu request or a regional habit passed along by baristas rather than a fixture on the board.
The idea is close to the way some cultures pair coffee with a wedge of citrus, but here the lime is not a garnish on the saucer, it is part of the drink itself. Hot espresso hits the fresh lime, the heat lifts the fragrant oils out of the peel and flesh, and the result is a cup that is at once bitter, bright, and faintly sweet. It is meant to be small and bracing rather than a long, sipping drink.
The key element: fresh lime meets hot espresso
The whole drink turns on one move, so it is worth understanding. Fresh lime, not bottled juice, is what makes a guillermo work. When you pour hot espresso straight over lime slices, the temperature coaxes aromatic oils out of the skin and releases the juice from the flesh, so you get citrus fragrance and tartness at the same time. Bottled or concentrate lime juice skips the peel entirely and tastes flat and sour by comparison.
Everything else is optional. Milk softens the edge and rounds the citrus into something almost creamy; ice stretches it into a cold refresher; a pinch of sugar tames the tartness if your limes are especially sharp. But the two non-negotiables are the same every time: fresh lime and hot espresso poured directly over it.
Equipment you need
You do not need much. The list is short:
- An espresso source. A home espresso machine is ideal, but a strong stovetop moka pot shot works well too, and even a very concentrated brew will do in a pinch. If you are still finding your footing with the shot itself, our guide to how to make espresso at home walks through grind, dose, and extraction so the base of your guillermo is solid.
- Fresh limes. One lime is plenty for a drink or two. Look for fruit that feels heavy for its size, which usually means more juice.
- A small glass or cup. A short tumbler, a small rocks glass, or an espresso cup all suit the drink's small size.
- A knife and board for slicing, and a spoon if you want to press the lime a little.
- Ice only if you are going for the cold version.
Ingredients
For a single guillermo, gather:
- 1 to 2 shots of espresso (roughly 30 to 60 ml total)
- 2 fresh lime slices, or a couple of thin wedges
- Optional: a small splash of milk, dairy or plant-based
- Optional: ice, for the cold version
- Optional: a little sugar or simple syrup if you like it sweeter
How to make a guillermo, step by step
Once your espresso is ready to pull, the drink comes together in under a minute.
- Slice the lime. Cut two thin slices from a fresh lime and drop them into a small glass or cup. Thin slices give the hot coffee more surface to work against.
- Pull the espresso over the lime. Brew one or two shots of espresso and pour it directly over the lime slices while it is still hot. Pulling straight into the glass, rather than into a separate cup first, keeps the coffee as hot as possible when it hits the fruit.
- Let it sit for a few seconds. Give it five to ten seconds. The heat draws the citrus oils and juice into the coffee, which is exactly the point.
- Taste and finish. Drink it hot and straight for the purest version. Or, for a softer cup, add a small splash of milk. For the iced version, add the milk and then pour the whole thing over a glass of ice.
- Adjust to taste. If it is too sharp, stir in a little sugar or simple syrup; if you want more citrus, press one of the slices gently with a spoon before drinking.
That is the entire guillermo espresso method. It rewards fresh limes and a good hot shot more than any special technique.
Versions at a glance
There is no single official recipe, so treat these as the common shapes the drink takes. Some people swear by it black and hot; others always add milk and ice. All of them start with espresso poured over fresh lime.
| Version | Ingredients | Hot or iced |
|---|---|---|
| Classic guillermo | 1 to 2 espresso shots poured over 2 fresh lime slices | Hot |
| With milk | Espresso over lime, plus a small splash of milk | Hot |
| Iced guillermo | Espresso over lime, splash of milk, poured over ice | Iced |
| Sweetened | Any of the above with a little sugar or simple syrup | Hot or iced |
Hot or iced, with milk or without
Because the guillermo has no rulebook, the milk-and-ice question is really a matter of taste and tradition. Served hot and black, it is at its most intense: bitter espresso against sharp lime with nothing to soften it. Add a splash of milk and the drink turns rounder and gentler, the citrus reading more like a bright note than a jolt. Over ice, with that same splash of milk, it becomes a small cold refresher for a warm afternoon.
If you take the milk route and want it silky rather than just poured cold, a few seconds of steaming helps; our guide to how to make steamed milk covers getting a smooth texture without a lot of foam. Keep the amount small either way, though: the guillermo is supposed to stay short and bright, not turn into a full milky coffee.
How a guillermo differs from an espresso and a cortado
Strip away the lime and a guillermo is just an espresso, so the fruit is the entire point of difference. A plain espresso is coffee alone; a guillermo is espresso with lime, coffee plus that hit of fresh citrus oil and juice, which changes both the aroma and the finish.
It is a little closer in spirit to a cortado, in the sense that both are small, punchy espresso drinks meant to be finished quickly rather than lingered over. But a cortado is defined by a small measure of warm milk cutting the espresso, with no citrus at all, while the guillermo's defining twist is the lime. The sweeter, condensed-milk cousin, the cortadito, goes even further in the milk-and-sugar direction, which puts it at the opposite end of the spectrum from the guillermo's bright, tart profile. In short: milk drinks smooth the espresso out, and the guillermo sharpens it up.
A light note on caffeine
A guillermo is still an espresso drink, so it carries the caffeine of the one or two shots you pull. If you are sensitive to caffeine or trying to sleep well, it is worth going easy on it late in the day, the same as you would with any strong coffee. Fresh lime is a bright, everyday citrus, but as with any food and drink, responses vary from person to person, and this is general information rather than medical advice.
Beyond that, the guillermo asks very little of you: a fresh lime, a hot shot, and a few seconds of patience while the two get acquainted. It is a small drink built for a quick, tangy lift, and once you have made one, you will understand why the people who know it tend to keep it in their back pocket.