Chemistry of Beer - Unit 6 - Isomerization

[@samhazelton5052]

What flavors does isomerization give off?

[@stephenborntrager6542]

It in the case of alpha acids, it causes a massive increase in bitterness. Aside from that, the most likely thing to notice is a loss of aromatic compounds from the hops due to the fact that isomerization happens during the boil. Some brewers counteract this by adding additional hops right near the end of the boil, or even after fermentation in the case of "dry hopping." Almost everybody boils hops though, so that bitterness is generally considered critically important. Some say it can't be called beer without it.

[@tachikoma805]

You boil with hops to extract bitterness. You hop during fermentation to extract flavor/aromas. So isomerization increases bitterness but destroys aromatics. That's why you boil with some hops and ferment with others depending on the desired bitterness and aromatics in the resulting product.

[@gregolsen9059]

in brewing - isomerization does not introduce aromatics, it actually volatizes and destroys the specific oils that cause aroma/flavor. isomerization of alpha acids is important for introducing the bitterness in beer that balances sweetness from the malt. hops boiled for more than 10-15 minutes will lose essentially all of their aromatic qualities, although when hops are added at lower temperatures (end of boil, whirlpool, knock-out, fermentation, bright tank, etc.) the essential oils are dissolved into solution and their aromatics are much more noticeable.