Straight from the Coffee Geek's mouth

Wednesday, 5 December, 2012
All words by Craig Charity

This is a piece for Coffee Shops:

[Note from TheCoffeeMag: Don't accept bad coffee at any cafe, there are no excuses, read this to find out more about what should be happening at your local cafe to ensure the best possible cup]

I thought I would write an article on how to improve your coffee if you own a coffee shop.

If you are a coffee shop owner I assume that you have a commercial coffee machine and grinder. I am going to split this into two sections, cleaning and temperature.

A disclaimer before I start, these points are my opinion and not set in stone. I successfully owned a coffee shop in Hillcrest as well as a mobile coffee company so I have some experience in this.

Keep it clean!!!
Stand in front of your coffee machine and run water out of your group into a cup, let it cool and taste it. If you could not tell the difference between the water out of your group and water out of a Berg spring you are doing a flipping fantastic job. If however the water tastes more like an ashtray in a bar than water it is not so good.

Dirty vs. Clean

Coffee can only taste as good as the sum of its components. If you have bad water coming out of your group no matter what coffee you use or what machine you have it is not going to taste like it should.

There is a three way valve attached to your group head that allows your group to vent pressure after you have finished brewing your shot of espresso. You will hear a splash(sounds like ‘dooosh’, if it doesnt, you arent saying ‘dooosh’ right) of water when you press to button to stop your espresso. If that valve wasn't there you would have 9 bars of hot water above your coffee puck just waiting to sneeze on you when you unlock the portafilter from the group. Every time this pressure is vented back through your group and out the three way solenoid valve it causes some ground and dissolved coffee to get sucked through your groups’ internals. The coffee oils stick to the side walls and go rancid after about 45 minutes. Yes. 45 Minutes. That is why it is so important to backflush at least once a day, I suggest leaving a extra portafilter handle next to the machine and doing some non-detergent backflushes throughout the day.

If you still have bad tasting water, it is time to service your machine.


I did an article a while ago on the effects of temperature on coffee. Most of you will have heat exchanger machines, which have a single boiler with heat exchange tubes going through the boiler that heat water coming from your water mains before it gets to your groups. The water in the boiler does not come into contact with your coffee in the groupheads.

If your boiler is sitting on 1.2 bar pressure the water in it is about 125 degrees C, the large brass groups act to absorb the heat and give you water at a temperature that is cooler than that of your boiler. The barista can change the temperature of the water coming out of the group by how long he flushes the before he pulls his shot.

Flushing the grouphead

Check out for a incredible article on how to manage temperature on a HX (heat exchange)machine.

A simple way to test is to pull shots with no flush, 5 seconds, ten second flush and 12 second flush and taste them. You will be surprised how different they can be.

There is way more on this subject than just these two points but I just wanted to get you thinking...

What are those thoughts? We want to know!

Got something to say? Then leave a comment!