UNDER EXTRACTED

CORRECTLY EXTRACTED

OVER EXTRACTED

Light walnut

Beige-brown, with dark streaking

Dark brown edging, white or black circle in centre

Thin head with large bubbles

Thick head with very small bubbles

Thickness may vary. Light or dark medium-sized bubbles

Very brief
< 1 min

Long 3-4 min

Medium 1-2 min

No body; watery

Firm

Insufficiently firm

Insufficient aroma; light

Aromatic, full-flavoured, not bitter

Strong, bitter, astringent, woody, insufficient aroma

Very brief

Persistent

Brief aroma, persistent bitterness

Too coarse

Correct (1 ml per second)

Too fine

Insufficient
< 6.5 g

Correct 7 g

Excessive
> 7.5 g

Insufficient

High

Medium

Low < 86°

Correct 88°

High > 90°

Low < 9 atm

Correct 9 atm

High > 9 atm

< 20 sec

25 sec

> 30 sec

Old or badly stored coffee

  

Blocked filter

Clogged shower screen