Another Grinder Sick Note
April seems to have got off to a challenging coffee grinder month. This morning I got a call to check out the setting on a coffee grinder which had been installed as a temporary measure.
Everything looked OK, however the coffee was taking an age to grind any volume. The problem - blunt grinder blades. The impact on the coffee taste - profound!
The problem with blunt grinder blades is that rather than cut the coffee bean they tend to crush them. This results in the average particle size of the coffee to be all over the place. Anything from powder fine to quite gritty. It makes it impossible to set the grinder accurately for the espresso coffee machine. It also has the effect of putting a lot of excessive heat into the bean which in turn can result in the coffee tasting burnt.
Moral of the story - make sure you have a programme in place that ensures that the grinder blades are changed every so many kilos. A number I have seen used is 300 kilos of coffee per set of blades, but it will vary.
One of the easiest ways to remember to change the grinding blades is to change them when you have a major service on the coffee machine. There again, if you are in a high volume site the discs may need to be changed more often.
Grinders are always, in my experience, the last piece of kit that coffee shops consider when they experience problems with their coffee; it should in fact be one of the first places to look.
Tell tale signs of blunt blades - coffee appears quite powdery, the coffee appears to be taking an excessive amount of time to grind and finally the noise level of the grinder appears excessively loud.