Coffee News: from Seed to Cup

8 Steps to Purchasing the Perfect Espresso Machine

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You’re all set and ready to launch. You’ve found a great location for your new coffee shop. You’ve decided on most of your equipment. You’ve even planned the look and feel of the space. But there’s just one thing you haven’t finalised – which espresso machine to buy.

This is NOT an easy decision. In fact, this is one of the most important decisions you’ll make. But never fear, good friend. We’re going to guide you through this potential minefield by highlighting the eight decisions you need to make about your machine. In this way, you’ll be able to narrow down the best espresso machine for your business.

Spanish Version: 8 Pasos para Comprar la Máquina de Espresso Perfecta

 

latte art pour

In order to create the perfect coffee, your espresso machine has to exactly suit your needs.

  1. The Boiler Dilemma

Think of a steam-powered espresso machine, running extremely hot and so producing horribly over-extracted shots. You’ve just pictured what was commonly in use before the Wars (unless you were lucky enough to live in Italy in the early twentieth century).

The espresso machine as we know it is a comparatively modern piece of equipment. In fact, it wasn’t until the advent of heat exchangers in boilers (in the post-war period) that espresso started to taste something like it does today.

Heat exchanger based machines are common in many coffee shops. By running tubes (heat exchangers) full of brew water through a large steam boiler, they produce hot water. And not just any hot water, but water at the perfect temperature for coffee. By perfecting of the length of the tubes and the way the hot water circulates through the system, your machine can produce water with a fairly stable temperature and also provide lots of steam for texturing milk.

Sounds good, right? Well, it’s good but not great…

In recent years, the single-boiler heat exchanger machine has seen increasing competition from machines with separate boilers for brew water and steam. These multi-boiler machines have separate boilers for the brew water and the steam, meaning the temperature for each can be more precisely controlled. The main downsides of multi-boiler machines are increased complexity (and as such, increased expense) and the fact that brew water is idling in a boiler rather than being drawn fresh from the mains.

A small number of manufacturers – like La Marzocco, Synesso, Slayer – only produce multi-boiler machines. The majority of players in the speciality market, including Nuova Simonelli/Victoria Arduino, Kees Van der Westen, and Sanremo, offer multi-boiler machines at the high end. They also provide heat exchanger machines from their mid-range products down. Finally, there are a number of companies that only produce heat exchanger machines.

So does that mean the multi-boiler machine is the only option for a serious coffee shop? Well, yes and no. Heat exchanger machines can be made to work very effectively. For example, I’ve used the iconic, futuristic Kees Van der Westen Mirage (a single-boiler heat exchanger machine) extensively, and found it to be produce water at an extremely stable temperature even during busy periods. Sadly, though, not all single-boiler machines are made equal; most offer significantly reduced temperature stability compared to a good multi-boiler machine.

kees van der westen mirage

The Mirage by Kees Van der Westen

So for the sake of simplicity, let’s assume that we’ve settled on a multi-boiler machine for a medium-sized coffee shop. How, then, do we narrow down the field from this large number of machines that seem to fit the bill?

  1. Size Really Does Matter

Whilst an enormous four-group machine may look impressive, remember to be practical. It’ll be expensive to run and totally overkill for all but the busiest of coffee shops. If your projected volume is less than 40kgs per week (or, to put it another way, around 2,000 espresso-based drinks per week), you should opt for a two-group machine.

If you have your heart set on four groups, though, consider purchasing a pair of two-group machines (if funds allow). This will provide some flexibility should one of the machines malfunction.

SEE ALSO: Espresso Machine Maintenance: A VIDEO Guide to Draining a Heat Exchange Boiler

 

  1. You Need (Temperature) Stability in Your Life

Whilst many multi-boiler machines look similar on paper, their ability to produce brew water at consistent temperatures varies greatly.

Almost all modern multi-boiler machines will have a PID (proportional-integral-derivative) controller taking care of brew boiler temperature. In simple terms, PIDs regulate the temperature of the water in the boilers, but they do this with much greater precision than the traditional thermostats. They also enable users to set a specific temperature for brew water. Some older La Marzoccos did without PIDs but, should you be considering something like a used Linea, they are easily retrofitted.

Given that most multi boiler machines use similar PID controllers, any variability in temperature stability can be a consequence of other factors. Of these, I believe the most important are grouphead design and the mechanism by which fresh water is fed to the brew boiler.

  1. It’s All in Your (Group)Head

A poorly-designed grouphead will either suck temperature out of the brew water or become too hot and scald the grounds. So what’s the solution?

For many years, the E61 grouphead design, which circulated hot water constantly through pipes to the grouphead and back to the heat exchanger, was considered to be the best option.

E 61 group head

The E61 grouphead in action.

More recently, though, the saturated grouphead (and variations of that) has found favour due to its superior temperature stability. This type of grouphead is bolted directly to the brew boiler and hot water is allowed to flow through the open neck of the brew boiler into the group.

A third and even more precise solution is to place a heating element in the grouphead itself, allowing users to control the temperatures independently of brew boiler temperature.

In reality, any of these three systems, when properly implemented, will provide sufficient temperature stability. It’s only the lower end machines that suffer from variations in brew water temperature great enough to affect the taste of the espresso.

  1. Keepin’ It Fresh

The other major factor that influences stability is how water is fed into the boiler. Multi-boiler machines have relatively small brew boilers (often one for each group). Early versions (and a few current ones) feed fresh water, which is at room temperature, directly to these boilers. Under heavy use, the brew water is a combination of heated water and this fresh water that has had insufficient time in the boiler to heat up. The unfortunate result is a steady and significant reduction in brew temperature over a series of shots. Clearly this can lead to consistency issues – particularly in a busy coffee shop.

One solution is to use pre-heated water, which is then run through a heat exchanger before it reaches the brew boiler. Most multi-boiler machines now have this feature, but it is worth noting that some very popular machines only offer it as an option. Should you find yourself buying one of these models, the extra expense of specifying pre-heaters is definitely worthwhile.

We’ve narrowed down the shortlist of machines to ones with good grouphead design, PID-controlled multi-boilers, and preheating of the fresh water feed. Now it’s time to examine other factors that influence the quality of the drinks produced and the efficiency of the process.

  1. The Pre-infusion Tango

Some form of pre-infusion is important. This involves the machine wetting the grounds at a relatively low pressure before ramping up to full pressure. The benefits? It minimises the possibility of channeling the shot and it also reduces fines migration, which can partially block the basket and slow extraction.

Pre-infusion can be achieved through a number of mechanisms. The upper-end machines from companies such as La Marzocco and Sanremo allow the pump pressure to be controlled throughout the course of the shot. This is known as pressure profiling. Others, such as Slayer, use flow profiling; the flow of brew water is manipulated, to similar effect, via variable restrictors.

Most machines with pre-infusion capabilities, however, have a simpler system. Here, only the first few seconds of the extraction can be set at a lower pressure. Sometimes this is adjustable, in terms of length, but more often it is fixed.

Another good question is whether it’s worthwhile investing in a machine that has flow/pressure profiling (variable pressure) or whether a fixed pressure machine with pre-infusion will suffice. In my view, most of the benefits of a machine with variable pressure come from its ability to perform a long pre-infusion. So fixed profile machines that offer a similarly long initial pre-infusion have many of the advantages of a variable pressure machine – but they deliver them without increased complexity and costs.

Sanremo Opera

The Sanremo Opera at Colonna & Smalls: Long pre-infusion plus straight 6 bar extraction.

  1. Defying Gravity: Weight vs Volume

Wouldn’t you just love an automated shot process? This can speed up workflow whilst maintaining the consistency of your shots. If this appeals to you, you have two options: gravimetric machines and volumetric machines.

Gravimetric machines have gained a lot of traction in the last year or so. They work by weighing the output dose of the espresso shot being pulled. This is achieved by having scales built into the drip trays and connected to a control unit. When the programmed brew ratio is reached, the control unit stops the shot.

Manually managing this process for many groups is both resource intensive and tricky during busy periods, so any system that automates this should be a worthwhile investment. Unfortunately, the technology is currently a little inconsistent. It works well in some scenarios (for instance, when running a single coffee), but struggles in others (such as when you need to switch quickly between different beans, especially in cases where different brew ratios are used.

A simpler solution is a volumetric machine. These contain a flow meter that measures the volume of water dispensed, then stops it at a point set by the user. Although in theory this is less accurate than a gravimetric system, in practice it can work effectively. But buyer beware: some machines seem to have better volumetric capabilities than others. It’s definitely worth testing this functionality before committing to a purchase.

Of course, it’s possible to run a relatively high-volume coffee shop whilst manually weighing inputs and outputs. This is still the most consistent way to make espresso, as long as the baristas are well trained. But as gravimetric and volumetric machines are perfected in the years to come, they may become the more precise and more attractive option.

  1. Looks Aren’t Everything – But They’re Important

The final important elements are aesthetics and branding. These are linked in the sense that the best-looking machines are generally built by the manufacturers with the best reputation within the speciality coffee industry. Your espresso machine acts as a signifier of intent, so it’s vital that it matches the ethos of your shop.

Only a minority of customers, in my experience, will be interested in the technical details of your specific machine. However, a large proportion will have knowledge of the types of machines that are generally found in quality cafes. A customer of this kind, who might be waffling over whether to come into your shop, can be drawn in by the presence of a “good” machine.

The only caveat here relates to what I call “over-speccing”. In more simple terms, it means purchasing the most complicated, expensive machine because it is perceived as the best. In some cases, this leads to unnecessary expense with no benefits. In others, it can actually be detrimental to the quality of the coffee if the user doesn’t understand the complexities of the machine – making it a lose-lose situation.

To avoid this, you simply need to be honest with yourself. If you intend to run a high-volume shop with a single, blended espresso, then a pressure profiling machine is probably overkill. If your primary products are high-end single estates and single origin espressos, then it makes sense to purchase a top of the range machine that will extract the very best from these coffees.

No matter the type, espresso machines make a very big dent in the set-up costs of a new coffee shop. Despite this, they are surprisingly economical. With regular servicing and suitable filtration, a good machine can potentially generate hundreds of thousands of pounds of income during its lifespan. Not bad at all, given that really it’s just a very advanced water heater and pump.

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Written by J. Prestidge and edited by K. Beard.

Feature Photo Credit: Dianne Wang

Perfect Daily Grind.

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