The colour green – or why hops ought to be selected in the dark

Green is the colour of hope. The word is derived from the Old High German verb “gruoen”, meaning “to grow”, “to sprout” or “to flourish”. No wonder that hops are green, then. But do they have to be? Does colour tell us anything about quality? What are we looking for in hops? Do they have to look good? Does anyone ever see them, apart from the brewer, his apprentices and the people in the lab? Aren’t the inner values the important thing about hops – as with(almost) everything else?

A few weeks ago, a picture of dried cones of the same hop variety, but from two different suppliers, appeared on Twitter. One batch was a lush green; the other was more light green to yellowish in colour. And immediately the tweeting started: Is that possible if they’re the same variety? Should such a – supposedly less attractive – batch be accepted at all?

The colour of hops is influenced by several factors. On the one hand, it is variety-specific. Another important variable is the time of harvest. The initially rather dark green cones mostly take on a light green to yellow, – or even brown – colour in the course of the ripening process. The location of the hop garden and the microclimate there also affect the colour. Periods of rain accelerate the changes in colour. And, last but not least, diseases and pests have a direct influence on the colour of the hops. Another factor that should not be forgotten is the drying process, which can of course have a strong influence on the resulting colour.

Naturally, the appearance of the hops should not be ignored, but when it comes to hop selection, it mainly comes down to the aroma. And that changes, depending on the time of harvest. For some varieties (e.g. Hallertau Mittelfrüh), a later time of harvest is a positive factor for a better and more intense aroma. For other hop varieties (e.g. Cascade), a time in the middle of the harvest season produces the best and most typical hop aroma. The optimum time of harvest with regard to aroma aspects therefore has to be determined with the aid of brewing trials – and colour should not be a criterion here.

When it comes to pellets, things are a little different. In this case, the cones are ground and the proportion of the lupulin glands (yellow) has a direct influence on the colour of the pellets. Therefore, the higher the alpha and oil content is, the lighter green the pellets are in colour. Unfortunately, this also applies to oxidation processes. They, too, have the effect of turning the lush green to yellowish green during the ageing process. However, this can easily be established through sensory perception or by means of HSI analysis. The colour specificity of the variety naturally also plays a part in the colour of the finished pellets!

So don’t allow yourself to be distracted by the colour of the hops. Perhaps we ought to select hops in the dark in future. By analogy with the proverb “Beauty lies in the eye of the beholder”, for hops we can say “The best aroma lies in the nose of the selector”. Or, to put it more pithily, in the words of David Grinnell (Boston Beer Company) “Hop selection is not a beauty contest”.


One Response to “The colour green – or why hops ought to be selected in the dark”

  1. Annika says:

    “Hop selection is not a beauty contest.” My new favourite quote 🙂

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