Variations in Hop Aroma Depending on Crop Year

As in previous years we would like to demonstrate the variations in the contribution of hop oils to beer depending on the crop year. As a representative hop aroma substance we have chosen linalool, which correlates well with the sensory impression of a hoppy aroma in beer.

The alpha and linalool concentration can vary independently of each other, which means that, in a year with higher alpha values, the linalool concentration does not necessarily increase by a similar amount. Because of this we calculate, for each variety, the ratio of linalool (ppm)/ alpha (% HPLC, EBC 7.7) to indicate how much aroma is dosed by adding the same amount of bitterness. This is very significant in the case of late hop addition.

"Graph"

As can be seen in the chart above, the data from crop 2011 is very similar to 2010 for Perle and Select, whereas Tradition and Saphir are significantly lower this year. By adding the same amount of alpha, there will therefore be a correspondingly lower contribution of linalool with these two varieties.

Variety Relative difference

Perle not applicable

Tradition - 35 %

Select + 7 %

Saphir - 47 %

Owing to the very low levels of the ratio linalool / alpha and normal analytical fluctuations, the change in Perle can be discounted and is not therefore shown in the table above.

Although this year’s differences are not as extreme as last years, it is normally recommended to base late hopping calculations on the hop oil concentration in the hop product to be used. In the above diagram only some examples are shown. Of course this data is available for all of the important varieties. Please contact us if you need any further information or technical support.

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