Page 10 - APPD - Something's_Brewing_Jan_Feb23

www.beveragestandardsassociation.co.uk
Vol.28 | January/February. 2023

Espresso Machine Focus

Temperature Control
Quite simply a coffee machine needs to stay at optimum temperature to ensure the group head and
water temperature at point of infusion stays at 90-95°C. Most coffees are made from only around 1 fluid
ounce of water (espresso) allowing the machine to remain stable during slow and busy times.

Taking out lots of hot water for tea, however, means replacing it with cooler water. This has two main effects:
• Espresso coffee being under extracted (weak and sour tasting coffee)
• Reduced steam availability or power for working the milk.

Consider a separate water boiler if any volume of tea or hot water will be required

Hot Water Output

Standard configuration machines will vary in temperature, some far more than others, but they will all vary to
some degree.
In simple terms, group head temperature rises, sometimes higher than 100°C when machine is not being used
and cools down well below 90°C when being heavily used. Coffee infuses properly usually between 90 and 95°C.
Hotter than this and more bitterness is extracted by over extracting and burning the sugars. Too cold water will
limit presence of sugars and extract primarily sour tasting components.

Although hot water is available from espresso machines, if you plan to use lots of it for pots of tea or large cups of
tea, you will impair the performance of most espresso machines during busy times.

Skilled Baristas keen to produce consistent tasting drinks will try to mitigate these effects, particularly of
overheating, by flushing repeatedly before each espresso extraction. You will sometimes see this with as many as
6 or 8 flushes.
Even with this level of skill there is of course still a variability in coffee extraction and flavour as no Barista can
‘know’ what the temperature inside the group head is.

It is probably fair to say that as with everything, “you get what you pay for”. Generally, the more expensive
machines will be more temperature stable, with heavier componentry, larger boilers; and more power.

This not only avoids the inconsistency issues but also gives the ability to set the machine to ‘optimise’ extraction
by finding the ‘sweet spot’ of each coffee. This results in a far higher quality and consistency of extraction, i.e.
consistently good coffee, more or less regardless of Barista skill level.

It also means less wastage, throwing away of unwanted shots.
So, is Temperature Control Right for You?

As with any product there are no real rights and wrongs. Non temperature-
controlled machines have been around for almost a century and we have enjoyed
coffee from them for all those years.

An interesting point to note is that most TCS (Temperature Control System) machine
purchasers are second machine owners. Most first-time buyers can’t really see the
value of temperature control and therefore the price differential deters them.