You’ve hit the coffee shop and opted for a good old double shot of espresso. But what you may be wondering is how much coffee you should actually be getting.
We decided to dig a little deeper into the topic and figure out exactly what the differences are between a single and double espresso shot.
Spoiler alert: it’s not as straightforward as you might think.
Espresso is a type of coffee made by forcing hot water (around 90 degrees celsius) through finely ground, tightly packed coffee beans.
After being ground, the beans are packed into a container known as a filter basket, which is then placed within the portafilter, to be attached to the espresso machine.
Espresso can be made with any type of roast and a variety of beans.
Espresso is thick, like warm honey, due to the pressurized brewing process. The brewing process forces the oil in coffee beans to dissolve in water, creating a very concentrated beverage with a variety of flavours and chemicals.
The secret to espresso’s taste are the three dispersed phases of extraction:
- Emulsion of oil droplets
- Suspended solids
- Layer of gas bubbles or foam, forming what is known as “crema“
Single espresso shots
A single shot of espresso, or a “solo”, was developed because it was the maximum amount of coffee that could be extracted by traditional Italian espresso machines.
A single shot of espresso is made with 7 grams of finely ground espresso beans and yields about 30 millilitres of coffee (about 1 ounce).
Single filter coffee baskets are easily identifiable by their unique funnel shape. A single basket will hold between 7 and 12 grams of ground coffee.
Somewhat confusingly, single espresso shots are often made with double baskets, with the shot split between two cups.
Until very recently, baristas gauged a shot by sight, so would wait until the liquid espresso hit the 30ml mark before stopping the flow.
Double espresso shots (Espresso doppio)
A double shot of espresso is made using 14 grams of finely ground coffee and produces about 60 millilitres of liquid espresso (about 2 ounces).
A double filter basket will generally hold between 14 grams and 21 grams, with walls that are straight or slightly tapered.
While the traditional doppio espresso recipe calls for 14g of ground coffee, in reality, coffee shops will use anything ranging from 14g – 22g.
The problem with single baskets
Ideally, you’d use the same ground coffee to make half the amount of coffee with a single basket as you would with a double basket and get the same flavour.
However, using a single basket in this manner can lead to under-extraction or bitterness.
A single basket of coffee usually requires a coarser grind, or more coffee in the basket, to produce the desired taste.
Although they can be useful to home baristas, single baskets have become largely obsolete in coffee shops as they are inefficient and expensive to use.
Measuring by volume vs weight
In recent years, with the rise of specialty coffee, baristas have moved away from measuring espresso by volume, instead favouring weight.
The reason for this is quite simple:
A well-pulled espresso shot will have a layer of crema on top, which will contribute to the measured volume.
So while a standard double shot will have 60ml total volume, as the crema breaks up, the amount of espresso left over could be anywhere between 40 – 55ml.
By switching to measuring by weight, a barista is able to measure the volume of the espresso shot more accurately.
All is not what it seems
You may be getting the sense by now that there is no set way that things are done when it comes to single and double espresso shots.
And you’re completely right.
There’s really no standard anymore for distinguishing between single and double shots.
The amount of ground coffee used, and the final volume will vary widely between coffee shops, including those who know what they are doing.
While this may sound a bit chaotic, in reality, it is one of the ways that coffee is so interesting and continues to evolve.
How to make a double espresso shot?
First, you’ll need to make sure your espresso machine is clean and that any old coffee grinds and residue have been removed from the group head. To do this, simply press the button that sends water through the machine and use a cloth to wipe away any dried coffee. This is called purging.
The next step is to grind 22g of coffee. This is based on the Australian industry standard recipe discussed in our Espresso Grind Guide. Grinding it into the double filter basket then tamp it to the desired level of compactness. Tamp it in one firm motion.
Attach the portafilter firmly to the group head.
The final step is to extract the espresso. Simply turn on your coffee machine’s water flow and it will flow through your compact bed of coffee grounds.
You’re looking for 44g of espresso (yield) which should take 27-31 seconds.
How much caffeine is in each espresso shot?
Espresso has more caffeine per unit volume than most coffee beverages, but a typical serving size is much smaller.
Therefore, the total caffeine content is less than in a mug of American-style filtered drip brewed coffee.
A double shot contains roughly 60-100mg of caffeine, according to the National Coffee Association (NCA).
However, this depends on factors such as bean origin and roast method.
In contrast, a typical serving of drip coffee contains between 150 and 200 mg.