Order an espresso at a bar in Milan and you get about 7 grams of coffee in roughly 25 millilitres. Order one in a specialty café in London, Melbourne or Seattle and you will usually get a double without being asked, made from 18 grams or more. Both are called espresso, both are correct, and the difference between them is far more interesting than "one is twice the other". This guide covers what single and double shots actually are, where the numbers came from, what changes in the cup, what does not, and which one you should be pulling at home.
The Short Answer
A double shot uses roughly twice the ground coffee of a single and produces roughly twice the liquid. If the brew ratio is the same, the two drinks have about the same strength per sip. What doubles is the volume and the caffeine, not the intensity.
| Single (solo) | Double (doppio) | Triple (triplo) | |
|---|---|---|---|
| Ground coffee (dose) | 7 to 10 g | 14 to 20 g (18 g is the modern norm) | 20 to 22 g |
| Espresso out (1:2 ratio) | 14 to 20 g | 28 to 40 g | 40 to 44 g |
| Approximate volume | about 25 to 30 ml | about 50 to 60 ml | about 75 ml |
| Shot time | 25 to 30 s | 25 to 30 s | 25 to 35 s |
| Caffeine (arabica, rough) | about 50 to 80 mg | about 120 to 180 mg | about 150 to 220 mg |
| Basket shape | Small, tapered, funnel-like | Straight or slightly tapered | Deep, straight-walled |
| Ease of dialling in | Hard | Easy, the reference | Moderate |
Notice the shot time row. A double does not take twice as long. Both are pulled in roughly the same 25 to 30 seconds, because the double basket is wider and deeper to match the larger dose.
Where the "7 Grams" Came From
The single shot is not an abstract unit. It is half of a commercial double. For most of the twentieth century, a standard Italian café portafilter basket held about 14 grams of coffee. Bars pulled that double through a twin-spouted portafilter into two cups side by side, and each cup received the output of about 7 grams. One extraction, two customers, no waiting. That is where the idea that "a single is 7 grams" comes from, and it is still how many bars in Italy work today.
The number was later written into a formal standard. The Istituto Nazionale Espresso Italiano, the body that certifies bars allowed to serve "Certified Italian Espresso", defines it like this:
The same standard puts the finished drink at about 67 °C in the cup. Two things are worth noticing. First, 25 ml of espresso with crema weighs noticeably less than 25 grams, so the Italian single is closer to a 1:2 to 1:3 ratio by weight than people assume. Second, this is a single per cup. Nothing in it says the coffee has to come from a single basket.
How the Double Became the Default
Outside Italy, three forces pushed cafés towards the double over the last few decades.
- Bigger milk drinks. A 7 g shot disappears in a 350 ml latte. As cup sizes grew, especially in North America from the 1990s onwards, one shot stopped being enough to taste the coffee, and chains standardised on two shots for medium and large drinks.
- Consistency behind the bar. Baristas found that a double basket produced a more even, more repeatable shot than a single basket. Many specialty cafés quietly stopped using single baskets at all and switched to bottomless portafilters with doubles only.
- Dose creep. The "double" basket itself grew. What was 14 g became 16 g, then 18 g, and today 20 to 22 g baskets are common. The word "double" now describes a basket size, not a precise quantity.
Three Ways to Make a Single
This is the part most comparisons skip, and it explains most of the confusion. A "single shot" can mean three physically different things:
| Method | How it works | Taste compared with a double |
|---|---|---|
| Split shot | Pull a double through a two-spout portafilter into two cups | Identical. It is literally half of the same double |
| Single basket | 7 to 10 g in a small, tapered single basket | Different. Needs a finer grind and extracts differently |
| Small straight basket | 10 to 14 g in a precision basket with straight walls | Close to a double, and much easier than a tapered single |
If a café hands you a single from a spouted portafilter, you are drinking half of their double. If you pull a single at home from the small basket that came with your machine, you are brewing something genuinely different, and usually harder.
Why Single Baskets Are So Hard
If you have ever dialled in a double beautifully, switched to the single basket with the same grind, and got a sour, gushing mess, you are not alone. Single baskets are notoriously difficult, for reasons that are mostly geometry.
- The funnel shape. To hold only 7 to 9 g at a reasonable depth, most single baskets taper sharply towards a small floor. The puck ends up deep in the middle and thin around the edges.
- Water takes the short path. Flow through a coffee bed follows the path of least resistance. A thinner bed at the edges offers less resistance, so water rushes down the sides and the centre under-extracts. The result can taste sour and bitter at the same time.
- The tamp is uneven. The sloped walls support the coffee at the edges, so the outside of the puck compacts before the middle does. Density ends up uneven even when the tamp looks level.
- Small errors are big errors. A 0.3 g dosing mistake is about 4% of a 7 g dose but under 2% of an 18 g dose. Every inconsistency in grind, distribution or dose is magnified.
- Less thermal mass. A small puck in a heavy portafilter heats and cools differently from a large one, which shifts the effective brew temperature.
Do They Actually Taste Different?
At the same brew ratio and the same extraction, a single and a double are the same beverage in two sizes. Strength, which coffee people measure as total dissolved solids, is set by ratio and extraction, not by how much coffee went in. An 18 g double pulled to 36 g and a 9 g single pulled to 18 g should land at roughly the same strength.
In practice, basket singles tend to differ in a few recurring ways that baristas describe consistently:
- Lighter body. Singles often feel thinner in the mouth.
- Brighter, more acidic. Partly real, partly the side effect of uneven extraction around the edges of the puck.
- Less forgiving. The window between a great single and a bad one is narrower, so shot-to-shot variation is larger.
- Less crema, simply because there is less coffee producing it.
Some people genuinely prefer the clarity of a well-made single, especially with light-roasted coffee. That is a valid taste, but it has a cost in consistency. The double is the easier place to learn, which is why nearly every recipe you read online, including ours, is written around it.
Caffeine: Single vs Double
This is the difference that matters most to many people, and it is roughly linear: twice the coffee in, roughly twice the caffeine out. A commonly cited reference value is about 63 mg of caffeine in a one-ounce (30 ml) single shot, which puts a classic double at about 125 mg. Real-world numbers vary much more than that suggests.
The three things that move caffeine the most:
- Dose. The largest single factor. A 20 g double has almost three times the caffeine of a 7 g Italian single.
- Species. Robusta contains roughly twice the caffeine of arabica. Many Italian and supermarket espresso blends include some robusta; most specialty coffee is 100% arabica.
- Ratio. A longer shot extracts a bit more caffeine, but far less than you might think. Most caffeine dissolves early. A lungo is not twice as caffeinated as a ristretto.
A useful home rule of thumb for arabica: expect roughly 7 to 10 mg of caffeine in the cup per gram of coffee in the basket. That gives about 50 to 70 mg for a 7 g single and 125 to 180 mg for an 18 g double. For context, the European Food Safety Authority considers single doses up to 200 mg and daily intake up to 400 mg unproblematic for healthy adults, and 200 mg per day during pregnancy. A big 20 g double with a robusta blend can reach 200 mg on its own.
Singles and Doubles in Every Ratio
Single and double describe how much coffee. Ristretto, normale and lungo describe how much water you push through it. The two ideas combine freely, which is why "double ristretto" is a perfectly sensible order.
| Style | Ratio | Single (9 g in) | Double (18 g in) | Character |
|---|---|---|---|---|
| Ristretto | 1:1 to 1:1.5 | 9 to 14 g out | 18 to 27 g out | Syrupy, sweet, intense, lower extraction |
| Normale | 1:2 | 18 g out | 36 g out | The balanced reference point |
| Lungo | 1:2.5 to 1:3 | 22 to 27 g out | 45 to 54 g out | Lighter, more bitter edge, higher extraction |
For a deeper look at how ratio shapes flavour, see dose, yield and brew ratio explained.
Which Shot for Which Drink
The more milk or water you add, the more espresso you need for the coffee to still taste like coffee. These are sensible starting points, not rules.
| Drink | Typical size | Suggested base |
|---|---|---|
| Espresso | 25 to 60 ml | Single in Italy, double in most specialty cafés |
| Macchiato | 60 to 90 ml | Single or double with a spoon of foam |
| Cortado / gibraltar | 120 to 140 ml | Double, milk roughly equal to the espresso |
| Traditional cappuccino | 150 to 180 ml | Single is traditional; double for a stronger coffee taste |
| Flat white | 160 to 180 ml | Double, often double ristretto |
| Latte | 240 to 350 ml | Double; triple for large sizes |
| Americano | 180 to 350 ml | Double, water first then espresso to keep the crema |
| Iced latte / iced americano | 300 to 450 ml | Double or triple; ice dilutes as it melts |
Which One Should You Pull at Home?
For most people the honest answer is: pull doubles, and deal with the quantity some other way. The double basket is where your grinder, your technique and almost every published recipe line up. Once it is dialled in, it is forgiving.
If you want less coffee or less caffeine, you have better options than fighting a tapered single basket:
- Split the double. Use a spouted portafilter and serve two cups, the Italian way. Nothing to re-dial.
- Drop the dose a little. Most double baskets work within about ±1 g of their rated size, so a 16 g basket or a smaller straight-walled precision basket (12 to 15 g) gets you part of the way without the funnel problem.
- Use a decaf or half-caff blend if caffeine, not volume, is the real concern.
- Pour less milk rather than using less coffee, if the issue is that the drink feels too big.
How to Dial In a Single Basket
If you do want true single-basket shots, go in knowing it takes more precision, and work in this order:
- Match the dose to the basket. Most single baskets want 7 to 10 g. Check the rating stamped on it or weigh a level, untamped fill. Overdosing leaves no headspace; underdosing leaves a soupy puck.
- Weigh to 0.1 g. On a small dose, eyeballing is not an option.
- Start finer than your double. Expect to go a few steps finer on the grinder to reach 25 to 30 seconds.
- Distribute carefully. A distribution tool with fine needles (WDT) helps even more in a single than in a double, because clumps have nowhere to hide.
- Tamp level, not hard. Uneven tamping on a tapered puck guarantees side channelling.
- Aim for 1:2 first. 8 g in, 16 g out, in 25 to 30 seconds. Adjust only one variable per shot.
- Expect more variation. Judge a setting across two or three shots, not one.
If the taste is off, the diagnosis is the same as for any shot: sour means under-extracted, bitter and dry means over-extracted. The sour and bitter troubleshooting guide walks through the fixes, and the grind size guide explains why a single needs a different setting.
Bigger Doses and Triple Baskets
Going the other way works too. A triple basket (20 to 22 g, sometimes more) is common in cafés that serve large milk drinks. The same logic applies in reverse: a deeper puck adds resistance, so you will usually need a slightly coarser grind than your double to keep the time in range. A triple at 1:2 is not stronger per sip than a double at 1:2. It is simply more.
What It Costs: Shots per Kilogram
Dose also decides how long a bag lasts, which matters more than people expect when buying specialty coffee.
Dialling in costs coffee too. Plan on a few shots at the start of every new bag, and more if you are learning a single basket. A 250 g bag at 18 g per shot is about 13 doubles, and losing three of them to dialling in is a real share of the bag.
Common Myths
| Myth | Reality |
|---|---|
| A double is twice as strong | At the same ratio it is the same strength. It is twice as much |
| A double takes twice as long to pull | No. Both run about 25 to 30 seconds |
| A single is the "real" Italian espresso | Italian bars have long made singles by splitting a double |
| Singles and doubles use the same grind | A single basket usually needs a finer grind |
| A ristretto has more caffeine because it is intense | It usually has slightly less; intensity comes from less water |
| "Double shot" is a fixed amount | Anywhere from about 14 to 22 g in, depending on the café |
The Cheat Sheet
| Situation | What to do |
|---|---|
| Learning espresso at home | Double basket, 18 g in, 36 g out, 25 to 30 s |
| Want less caffeine | Split a double into two cups, or use a smaller straight-walled basket |
| Switched from double to single basket | Grind finer, weigh to 0.1 g, re-dial from scratch |
| Single tastes sour and bitter at once | Edge channelling. Improve distribution and level the tamp |
| Latte tastes weak | Use a double or triple base, not a longer shot |
| Recipe just says "double shot" | Assume 18 g in and a 1:2 ratio unless told otherwise |
| Watching caffeine | Count grams in the basket, about 7 to 10 mg per gram for arabica |
Frequently Asked Questions
What is the difference between a single and a double espresso?
A single shot uses about 7 to 10 g of ground coffee and yields about 25 to 30 ml. A double uses about 14 to 20 g and yields about 50 to 60 ml. Both are pulled in roughly the same 25 to 30 seconds. At the same brew ratio they have about the same strength per sip; the double simply gives you twice as much, with roughly twice the caffeine.
Is a double shot stronger than a single?
Not per sip, if both are brewed at the same ratio. Strength depends on the ratio of coffee to water and how well the coffee is extracted, not on the total amount. A double contains more coffee in total, so it has more caffeine and tastes more present in milk drinks, but a sip of each tastes about as intense.
How much caffeine is in a single vs a double espresso?
A commonly cited value is about 63 mg for a single and about 125 mg for a double, but real shots vary widely. For arabica coffee, a useful estimate is 7 to 10 mg of caffeine per gram of ground coffee, so a 7 g single has about 50 to 70 mg and an 18 g double about 125 to 180 mg. Blends containing robusta can have close to twice as much.
How many grams of coffee are in a double shot?
There is no single standard. A traditional Italian double is about 14 g, while most specialty cafés today use 18 to 20 g, and some use 21 to 22 g baskets. When a recipe says "double shot" without numbers, 18 g in and 36 g out is a reasonable assumption.
Why is a single shot harder to make than a double?
Most single baskets are tapered like a funnel, so the puck is thick in the middle and thin at the edges. Water flows faster through the thin edges, which causes channelling and uneven extraction. Small dosing errors are also a larger percentage of a small dose. Singles usually need a finer grind, more careful distribution and more precise weighing.
Does a double shot take longer to pull?
No. A double and a single are both typically pulled in about 25 to 30 seconds. The double basket is wider and deeper to hold the larger dose, so water passes through it in about the same time.
Should I use a single or double basket at home?
For most home baristas the double basket is the better choice. It is more forgiving, easier to dial in, and matches almost every published recipe. If you want a smaller drink, split the double into two cups, use a slightly smaller straight-walled basket, or pour less milk, rather than fighting a tapered single basket.
What is a split shot?
A split shot is a double pulled through a twin-spouted portafilter into two cups at once. Each cup gets half of the same extraction, so it tastes exactly like the double, just in half the volume. This is how many Italian bars have traditionally served a single espresso.
Where to Go Next
Single or double is the first decision in every recipe, and it quietly sets the grind, the timing and the caffeine for everything that follows. Pick one, weigh your dose and your yield, and only then start chasing taste.
From here, the natural next reads are dose, yield and brew ratio, the grind size guide for the setting you will be moving, and how coffee freshness works, because even a perfect double tastes flat with stale beans.