hist-brewing: Hop Utilization and bitterness

OxladeMac at aol.com OxladeMac at aol.com
Thu Feb 4 17:20:24 PST 1999

 I have not searched the hist-brewing archives to see if this subject has
already been discussed - if it has, please forgive me.

I am working on recreating beer following Markham's three runnings method.
Markham clearly points out that the hops used for the first batch are strained
out and reused for the second and again for the third batches "without any
augmentation of hops or malt."

I am trying to correlate the bitterness for each batch with a modern IBU
measurement.  What effect would reusing hops have on the bitterness?  I am
assuming a 1 hour boil for each batch (Markham calls for an hour boil).  Since
the hop utilization curve continues to go up after 60 minutes before leveling
off around 90 minutes, can I assume that the difference in utilization numbers
between 60 and 90 is still available for the next boil?  Or would the lupulin
resin be totally stripped from the hops, leaving essentially nothing behind
for the next batch?  Would there be anything left (beyond trivial amounts) for
the third boil?  If there would be, how could I figure out/predict what the
IBU's would be?

I guess I could try it side-by-side with identical SG recipes of known IBU
amounts to see how the historical process compares.  I didn't know if anyone
out there had ever done anything along these lines to figure it out.  (Perhaps
one of the big breweries has?)

Next question - what were the characteristics of medieval hops, and what would
be there most modern equivalent?  (Assuming circa 1577-1615 England - i.e.,
Markham's period.)   Most things I have read on the subject all agree that
alpha acid content of medieval hops were most certainly lower than they are
today.  I have seen some people give ranges of 2-5% alpha acid.  Any thoughts
on this?  

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?

What type of modern hops would most closely resemble 1600 England?  I have
seen some championing fuggles or Goldings, but both are, if I remember right,
post 1750 developments.  Would it matter much?  Markham doesn't call for any
aroma or flavoring hops - they are added in at the beginning of the boil.  If
that were the case, the only thing you would get would be the bitterness -
would it really matter what type of hops you used?

Any comments would be appreciated.

Oxlade Lachlan MacKinnon

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