From Vol. 2, No. 12, April 2018
Dry hopping = spicy, pine, tropical
Boiling hops for 10 minutes = bitter, earthy, woody
Could it be that simple? Of course not, because timing is only one part of a flavor matrix that includes varieties used, malt profile, yeast selection, etc. Nonetheless, research at Campden BRI in the UK confirms the importance of timing when adding hops for aroma and flavor.
The experiment was conducted with lager beers and compared the sensory results obtained from hopping a beer with 10 minutes left in the boil, at the end of the boil, in whirlpool and in dropping. Sorry, the hop variety was not specified.
Panelists used 16 terms to rate the resulting beers. The “ten minutes left in boil” beer had the highest values for bitter, woody, earthy, astringent, linger and sour. End of the boil was highest in herbal, sulfury and grassy. The whirpool addition was not highest in anything. The dry hopped version was high in spicy, sweet, summer fruits, pine, citrus, floral and tropical fruit.
The highest total flavor extraction was achieved with the 10-minute boil, followed by end of the boil, dry hopping, and the whirlpool addition.
A key takeaway is to remember that all additions resulted in relatively high values for pine, citrus and fruits, but the flavors resulting from 10 minutes of boiling were more likely to mask these. Likewise, bolder summer and tropical fruits might mask more subtle character produced during the whirlpool.
The results are what we might have guessed, although the difference between an addition at the end of the boil and in the whirlpool is a bit striking.