hist-brewing: Hop Utilization and bitterness

[George De Piro]

Hi all,

Oxlade asks:

> I am trying to correlate the bitterness for each batch with a modern IBU
> measurement.  What effect would reusing hops have on the bitterness? 

The second and third batches will have little bitterness.  The alpha acids will be
extracted into the first beer, even though they will not all be isomerized, the
majority will be in that first beer.  The second and third beers
will be of considerably lower gravity, and therefore not need as much bitterness.
Still, I would guess that the third beer would be decidely sweet due to the lack of
balancing bitterness.  On the other hand, the high level of tannins in the third beer
will likely give an astringency to the beer that will help balance the sweetness.
Hmmm.

Oxlade continues:

> I have a theory that the alpha acid content of their hops was not as low as we
> might think.  This is, of course, purely speculation.  What is my reasoning?
> Well, books I have read on homegrown hops all state that homegrown hops will
> tend to be more bitter than commercially available hops due to the fact that
> homegrown hops are not mishandled as commercially harvested hops are.  I
> speculate that Medieval hop growers would have figured out that the yellow
> lupulin was the important stuff, and would handle their hops with the same
> care that modern hop homegrowers do.   (i.e., don't knock the lupulin off!)
> If that was true, I can see some of the low alpha content of their strain of
> hops being made up for by the gentle handling.  Any thoughts on this?

Ancient hop growers did not have the technology to protect their hops from
the ravages of oxidation regardless of what they might have figured out about
the importance of the lupulin glands.  Modern hop processing techniques
evolved largely to protect the hop from oxidation.

Quick drying, baling, and more extreme techniques like pelleting and CO2
extraction preserve alpha acids far better than any medieval farmer could
have dreamed.  Modern farming techniques (irrigation, fertilization, pest control)
coupled with modern breeding techniques must almost certainly produce hops of
higher AA than farmers of old could produce.

I view my own hop garden as very medieval:  I usually forget to feed and water
the plants and do nothing about pest control.  The hops are not more bitter than
commercial stuff, nor are they as aromatic.  I am a far better brewer than a gardener.

Oxalade then inquires:

> What type of modern hops would most closely resemble 1600 England?

Any low-alpha hop should do.  The long boil will not allow hop much flavor or aroma
to remain in the beer, so variety isn't as critical as the level of bitterness.
 I would try to find fresh leaf hops to mimic
what the medieval brewer would have access to, but I would use pellets
rather than ratty, old leaf hops (brewers of old would surely have preferred
fresh hops over cheesy, old ones).  If you want to get really crazy, seek out
some wild hops, or grow your own.  If you grow your own there is a chance
that they will be pollinated by a wild male and you will get seeds of a semi-
wild nature.  This happens to me every year. Perhaps hops derived from these
seeds would be a reasonable approximation of hops of old?

Have fun!

George de Piro  (Lord of nothing, and lately even my dog is ignoring me)


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