I've got more Bars than you!!!!

We've just had an instance of a customer querying the bar pressure of an espresso machine he recently purchased from us. He read in the manual that the pressure generated by the machine was 15 bars, however on the internet he had read that it should be 18 bars of pressure.

I was amazed that he should be so concerned about such high levels of pressure.

The mazimum level of pump pressure required to achieve a perfect espresso extraction is between 8 and 10 bars. When I talk about pump pressure, I mean the pressure at which the coffee machine drives the water through the coffee.

If the pressure is higher than this, the water will be driven through the coffee too quickly, and a poor extraction will be achieved. To counteract this you would need to grind the coffee finer still, however this would in turn put a strain on the coffee machine's pump.

I then reflected as to whether this huge bar pressure was necessary to generate steam? But of course it isn't, steam will be generated when the internal pressure of the boiler is just 1 bar.

The only thing I can therefore think of is that the machine manufacturers are in some kind of race to potentially achieve the highest pressures possible, much like the speedometer on your car.

Your car speedometer can go to a maximum of 180 mph, however most of us will never get above 70mph.

So although the pump can be set to 15 or even 18 bars of pressure this fact is unimportant, you only actually need a maximum pressure of 10 bars.

So please machine manufacturers can you explain this to the buying public, as at the moment there is total confusion. In your attempt to sell machines, you're using spurious information that only mis-informs your potential customer.

In conclusion to this blog, I would point out to any potential purchasers of espresso machines, that if the manufacturer states that the maximum pressure is anything less than 8 bars, you will never achieve a properly extracted coffee.