The long history of flavouring
beer with hops is just froth
compared with how long we
have been brewing: evidence
of alcoholic drinks made from
fermented grains dates back
some 13,000 years. The first
documentation of hop cultivation,
by contrast, is from just AD 736
in what is now Germany. Before
that, to give their drinks flavour,
ale brewers used gruit, a mix
of bitter herbs, flowers or roots,
including dandelion, burdock,
sweet gale, mugwort, ground ivy,
yarrow, horehound and sage.
In the UK, hopped beer
was probably first imported to
Britain from the Low Countries
in about 1400, and battled it
out with native, unhopped ale
for more than 100 years until a
combination of taxes and laws
gave hops the upper hand, turning
ale and beer into synonyms.
One theory for the introduction
of the Bavarian Reinheitsgebot,
or purity law, of 1516 that
mandated the use of hops in
beer – and similar decrees in
other parts of the Holy Roman
Empire – was that gruit herbs
were also used in pagan rituals.
The real breakthrough for
hops, however, was probably the
discovery of their preservative
function: unhopped beer can
go off in weeks, but boiling
the hops before their use in the
brewing process releases bitter,
preserving resins that allow
hopped beer to last for years.
Today, we have other
preservatives – and gruit is on the
rise again. More beers are now
flavoured by botanicals other than
hops, and an annual International
Gruit Day is celebrated on
1 February, as more and more
people go back to the roots.ROOTED IN HISTORY
Chris Simms believes
in life, liberty and the
pursuit of hoppinessof winter nights where the temperature
drops below freezing. This potentially
influences the hops’ crucial dormancy
period and gives pests such as insects,
bacteria and fungi more time to grow and
attack plants. That can also affect hop flavour:
some of the hoppy smell of beer comes from
antimicrobial compounds produced by the
plant as a defence against attackers.
One response is to create new, climate-
resistant hop varieties. The breeding
programme at Wye Hops in Kent, an English
county that is a traditional centre of hop
growing, is looking at between 3000 and
4000 varieties to find ones that will thrive
in different conditions – for example, coping
with milder, wetter winters and hotter
summers. But there are limits to how far that
goes. “No [hop] plant likes sustained heat of
two or more weeks of 30°C plus,” says Capper.
Similar projects are under way in the
US, says Doherty – as are more dramatic
initiatives (see “Beer goes south”, opposite).
But Capper for one thinks there may have to
be a more fundamental rethink of hops’ native
territories. The UK should be OK, she says, as
should New Zealand, because their maritime
climates are less likely to see stark changes. But
“I worry about Washington state, Oregon and
Germany in terms of climate change,” she says.
Hop growers may have no choice but to up
sticks. “Michigan now has a small hop-growing
area. The whole northern hemisphere industry
is likely to go north” to Alaska and Canada,
according to Nielsen – and also to extend
its range in Australia and New Zealand in
the southern hemisphere.
This wouldn’t be unprecedented. While the
European heartlands may have been pretty
much unchanged for hundreds of years,
“the US hop industry has a history of moving
to get away from disease and pathogens”,
says Nielsen. “One hundred years ago, it was
in upstate New York; 70 years ago, it was in
California; 30 to 60 years ago, it moved to
the Pacific Northwest. There is no guarantee
it will stay there,” he says.
That was mainly to escape mildew, a fungus
that, once established in a hop-growing area,
is nigh-on impossible to get rid of. Will climate
change prove to be a more implacable foe?
We can only hop for the best. ❚Hops are
checked after
picking in
Kent, UK18/25 December 2021 | New Scientist | 67