Diagnosis

Problem

Remedy

Unclean machine

Anything less than spotless brewers, portafilters and tubes spell trouble for your crema.

Why?

Bacteria are getting into the coffee.

Back flush with Jo-Glo espresso cleaning powder after each session.

Never leave a loaded group head on the machine, full of used coffee. Use a group head brush.

Bean to cup machines do a tablet clean for both the machine and milk foamers after every session

Fast extraction

The espresso flow should take between 22 and 28 seconds. Any less, and you won't get the oils out of your coffee - and it's the oils which form your crema.

Grind size too big? The water gushes through too quickly. Tamping matters just as much. Technically speaking, give it a 20 lbs tamp - then tap. A final 40 lbs tamp should be followed by a light "polish".

Make sure that the right amount of water is dosed through the group heads. Too little water leads to under extraction and too much water stretches the coffee and makes it bitter.

For bean to cup machines make sure the grinder settings and water volumes are correct.

Bean Quality

Poor quality beans make   poor quality espresso!

Green coffee beans from all origins are graded One easy way of checking the quality is the size of the beans (screen size) generally the larger the bean the better the quality. The bean sizes must all be uniform. Smaller beans roast quicker than large beans meaning that the smaller beans get over roasted before the larger beans are developed making the roast very bitter. Make sure that the beans are not roasted too dark, over roasted coffees loose their essential oils and produce flat acidic espressos.

Check that all the beans are uniform and in good condition a lot of commercial coffee roasting machines are air injected speeding up the roasting times however a lot of beans roasted this way shatter and are ruined.

Not-so-fresh

Would you serve stale bread? Then why serve stale coffee? The lack of crema is a dead giveaway.

Don't buy in bulk. Order small amounts of espresso beans, but regularly and make sure you no when your coffee was roasted to ensure freshness v ital to high quality coffee production

Coffee beans contain a balance of over 800 complex and diverse aromatic compounds. Studies reveal that noticeable changes in coffee bean aroma occur within two or three days, more obvious changes occur within 8-10 days and 70% of the total aromatics can be gone within three weeks.

Once opened, use the beans within three days. (Don't forget to store them somewhere cool and dark. It really does make a difference.) And always grind your beans strictly to order.