can reach some 5 metres up wires in hop fields
or ramble through hedgerows. Compounds
called alpha acids in the hop cones produce
their characteristic bitterness, but other
constituents, such as beta acids, essential
oils and flavonoids, mean hops can also add
citrus, grassy, floral or earthy flavours.
The recent boom in highly hopped craft pale
ales has only made the plant more important.
“Hops pull an extraordinary amount of weight
for our beers,” says Thomas Nielsen, research
and development manager at the Sierra
Nevada Brewing Company in California and
president of the US-based Hop Research
Nielsen. In 2018, a report in Nature Plants
raised fears that severe droughts and extreme
heat could lead to hop shortages, causing the
price of beer to shoot up still further.
We are already seeing the first bit. In recent
years, droughts in central Europe and the
north-western US have hit hop harvests.
“Hops are competing with Seattle and
Vancouver for water from the mountains,”
says Capper. In 2020, a significant chunk of
the Pacific Northwest crop was destroyed by
intense wildfires in the region, or had to be
rejected because smoke had tainted its flavour.
It isn’t panic stations quite yet: covid-19
lockdowns reduced demand so much that
there was actually a hop surplus in 2020.
Many brewers also keep stores of hops that
can last for years with the right care. But with
conditions in traditional hop-growing areas
predicted to worsen, the fear is that changes
in climate and weather could alter the taste
of the hops, their vigour or even, perhaps,
wipe them out entirely in areas where they
have grown for hundreds of years.
According to Colleen Doherty, a plant
scientist at North Carolina State University
in Raleigh, one effect is that nights are
warming faster than days as global
temperatures rise, reducing the numberBEER GOES
SOUTH
Council. “I like to think it is the hops that are
differentiating these products more than
anything else.”
But not all hops are born equal. Different
varieties with picturesque names like Fuggles,
Goldings, Citra, Hallertau and Saaz impart
their own distinct degrees of bitterness or
complex aromatics. Each prefers slightly
different growing conditions. Then come
the effects of local climate, soils, microbes
and processing, together known as terroir,
which brings subtle taste differences to hops,
just as it does to a fine wine.
“Terroir is very important,” says Ali Capper,
a hop grower and director of the British Hop
Association. The UK’s mild maritime climate,
for example, means hops have lower levels of
a compound called myrcene, leading to beer
with a more complex, delicate aroma. Those
subtle differences can disappear in a bitterer
beer, such as US-style pale ales. The UK brewing
industry’s increasing reliance on imported
hops, rather than local varieties, to satisfy
changing tastes is one reason why buying
a round of beers in a London pub feels more
and more like taking out a second mortgage.
But such developments are mere foam on
the body of the problem. For all their ubiquity
in beer, hops are particular about where they
grow. “It’s not a crop for the faint-hearted,”
says Capper. They need deep, high-quality
soil, windbreaks to give shelter and plenty of
moisture – but not too much, because that rots
their roots. They are also highly sensitive to
light. Flowering is triggered by the shortening
of the days after midsummer, with the cones
harvested in late summer. As the days close
in further, the plant goes into a resting phase,
dying back and storing food reserves in its
roots for the next season. Without adequate
cold over winter to encourage dormancy,
growth during the following spring can
be weak and unsynchronised.
This is why commercial hops are grown
only in specific areas within a temperate
“Goldilocks zone” between about 35° and 55°
north. This includes the Pacific Northwest
heartlands of Washington, Oregon and Idaho,
which together account for about 40 per cent
of global production, and areas of Germany,
the Czech Republic and the UK. There is also
some cultivation of hops at similar southern
latitudes, in places like New Zealand.
It is also why climate change gets hop
growers particularly hot and bothered.
“No matter who you are or what you think,
I don’t think anyone in the industry is
unaware of the climate situation,” saysANDREWERRINGTON/GETTY^ IMAGESLaunched in June 2021, Gator Pale Ale
is brewed using locally grown hops of
the Cascade variety. So far, so US craft
beer – only these hops were grown
exclusively in Florida.
This was a far from trivial exercise,
says Shinsuke Agehara at the University
of Florida in Gainesville, who led the
work. Hops are delicate flowers (see
main story). “The high temperatures
and hurricanes in Florida aren’t ideal,”
he says. There also isn’t enough of
the daylight that is crucial during the
summer months for hop flowering,
which Agehara’s team got around
by attaching LED night lights at the
top of the hops’ support poles.
That isn’t an entirely new idea: South
Africa, another country outside the
hop-producing “Goldilocks zone” in
temperate mid-latitudes, also grows
hops with help from artificial lights –
originally because the country couldn’t
import hops during the apartheid era.
Florida’s climate had other
unexpected effects. Rather than a
single crop of hop cones each year,
there are two, one appearing from
February to June, the next from June
to November. The two crops together
come to about 90 per cent of the
average annual yield in the hop-growing
heartlands of the Pacific Northwest.
That’s a boon, but most importantly the
beer proved popular: punters described
a pleasant, melon-like aroma.