Two groups or three?

In part one of this ebook, we briefly mentioned the importance of choosing the right number of groups when looking for your perfect espresso machine. In this article, we return to this subject in more detail, to help you make the right choice for your business.

Getting this choice right is an important and surprisingly complex decision. It depends not just on how busy your cafe is, but also on the style of drinks that you serve, and the way you staff your cafe.

Over the next few pages, we’ll describe what’s inside a group head, and help you estimate how many groups you need for your business. We’ll also show you how to make the most of a smaller machine, if the space in your cafe is limited.

What is a group head?

The ‘group head’ or ‘group’ is the part of the machine that the portafilter connects to when making a coffee. The more groups you have, the more coffees you can make simultaneously.

The portafilter (literally ‘portable filter’) is a handle with a basket on the end that holds the ground coffee. When you make an espresso, you load the portafilter up with coffee, then slot it into the group to start the brewing process. The group head is therefore the part of the machine where water meets coffee.

Each group allows you to make one double or two single espressos at any one time. So with a two group machine, you can simultaneously make four single espressos — or two flat whites, assuming you use a double shot for each.

This also means that the number of drinks you can serve from the machine depends on whether you mainly serve single or double shots. A traditional Italian espresso bar, serving mainly single shots, will not need as many groups as a modern specialty cafe that uses double shots for all of their drinks.

How fast do you need to go?

The number of groups you need depends on how many coffees you make in a day — but even more importantly, on how many coffees you need to make at any one time.

With two groups, a trained barista working by themselves at a reasonable speed can produce roughly one drink per minute, or 60 drinks per hour. Two baristas working on a single machine can produce around twice as much, perhaps 120 drinks per hour during a rush.These numbers are just rules of thumb: the exact number depends on the particular equipment used, the skill of the barista, whether all shots are weighed on a scale, and so on.

However, in real life baristas have to perform many tasks other than just making espresso drinks. For example, they may need to serve customers, restock fridges, clear tables, and so on. They also have to interrupt their espresso-making workflow to make other kinds of drinks.

With that in mind, a reasonable target on a two group machine is 30 espresso drinks per hour for a barista working alone, or 60 drinks per hour for two baristas working together.

If you expect to be making more drinks than that during your busiest time of day, then a three group machine will help your baristas be faster and more efficient.

On the other hand, if you’re making less than 10 drinks per hour, then a one group machine will be sufficient.

If you’re not sure which category your business will fall into, then we recommend choosing the larger machine. That way, the growth of your business will never be held back by not having enough capacity.

It’s better to buy a machine that your business can grow into, than to spend more money on upgrading later.

Other factors to consider

Three group machines have some additional advantages and disadvantages to consider when deciding what machine to buy.

For some cafes, a three group machine might be impossible just because of the power or space that such a large machine requires. Many three group machines need 3-phase electricity to run at full power, which is not always available. Three group machines are also large and heavy, which means they may not fit on every bar.

On the other hand, the larger machine has some benefits: the baristas have a larger working space, which can help them to work efficiently — especially when you have two or more baristas working on a single machine. Three group machines generally have larger boilers as well, which means there is more steam power available when you need it.

The third group also has some other uses — for example, if you have more than one espresso drink on the menu and want to brew one at a different temperature, a third group can be set aside for this. On some machines, the third group can even be set up to operate at a different pressure or even used to brew a kind of filter coffee.

Having three groups allows you to clean one group whilst still working on the other two, so you can easily clean the machine during service

For very busy cafes, even three groups may not be enough. Four group machines have become pretty rare, however. These days the busiest cafes, serving more than 400–500 drinks per day, typically install two separate two group machines instead.

This has several advantages over a four group machine:

• It means that one machine can be serviced or cleaned while the other is in use
• It also allows more baristas to work simultaneously, because there are more steam wands, and more space around the machines
• If the machine breaks down, the cafe can still operate using the second machine

An extra hand for small machines

If space is limited, it’s possible to squeeze more out of a limited number of groups by using extra portafilters

On a one group machine, for example, the barista can be preparing the coffee in one portafilter, while the machine is brewing espresso from a second portafilter

An example of a good workflow for this situation would be:

• Prepare coffee in one portafilter and start brewing
• While the espresso brews, prepare coffee in a second portafilter
• When the first espresso finishes, swap the portafilters and start brewing the second espresso
• While the second espresso brews, steam milk for two drinks
• Pour both drinks when ready
• Clean and reset both portafilters

Using two portafilters with a one group machine like this nearly doubles the barista’s output.

Taken to an extreme, this method allows baristas to handle very high volumes with a single machine. Multiple sets of portafilters allows several baristas to work on an espresso machine simultaneously.

An example of this workflow could be:

• Barista 1 prepares coffee in portafilters and passes them to Barista 2
• Barista 2 swaps the new portafilters with the used ones in the machine
• Barista 2 cleans the used portafilters and passes them back to Barista 1

With this workflow, each group on the machine can be brewing espressos back to back. Meanwhile:

• Barista 3 steams jugs of milk and passes them to Barista 4
• Barista 4 pours and serves drinks, cleans the jugs and passes them back to Barista 3

In this way, four baristas can work on a two group machine and produce hundreds of drinks per hour — provided that the machine and grinder are powerful enough to keep up.

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