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Revellers may not wake up on Christmas morning with a clear head but,
ironically, they might find that clear beer was the culprit. Lemonade-lookalike
beer is the next fad that could sweep the States, if American brewers have
their way. Already, soft-drinks manufacturers in the US have swamped consumers
with clear colas. Detergent manufacturers have followed suit with clear
shampoos. Now the transparency trend has reached the contents of the beer
glass.

Miller Clear, sold in 12-ounce (340-gram) bottles, is similar to Miller
Lite, a well-known ‘light beer’ that contains half the carbohydrates found
in most lagers. Eric Kraus, a publicity officer at Miller, based in Milwaukee,
Wisconsin, and the second largest brewer in the US, says that like most
other 12-ounce bottles of lager, Miller Clear contains 4.5 per cent alcohol
by volume. What Miller Clear lacks, besides the carbohydrates, are the compounds
that give lagers their characteristic straw colour.

‘The beer is brewed, fermented and aged in the traditional way,’ explains
Kraus. The difference is that just before bottling or canning, the beer
is subjected to a process called ultrafiltration. This removes all the
chemical compounds that would otherwise give the beer its usual colour.
It also blocks some flavour compounds, giving Miller Clear a distinct flavour,
and some of the larger sugar and starch molecules that add to the carbohydrate
content in conventional beers.

Because Miller has applied for a patent on the process, it is unwilling
to discuss the technique. Nor will it discuss in detail which compounds
are removed.

Stuart Molzahn, the research director of Bass, the largest British
brewer, explains that when a solution undergoes ultrafiltration, it is forced
through synthetic membranes with pores on the molecular scale. These prevent
large molecules, including colour compounds, from passing through but admit
the rest. He says that the pressures used in ultrafiltration are generally
quite low – between 200 000 pascals and 1 megapascal, equivalent to between
two and 10 times atmospheric pressure.

Many of the colour compounds in beer are similar to those in caramel,
the dark brown sickly substance obtained when sugar is burnt. In beer, the
caramel-like substances arise from so-called ‘caramelisation’ reactions
in germinated grains of barley, or malt – a key ingredient of beer.

During germination, starch is converted into the sugars that will make
alcohol in later stages of the brewing process. But brewers need to halt
the germination process before too much of the newly formed sugar is consumed
by the grains themselves as they form shoots. Brewers do this by roasting
the malt, causing caramelisation reactions involving sugars, and amines
which are the products of broken-down proteins in the malt.

‘When you roast the malt, you get caramel-like compounds. The malts
in lagers are roasted at 65 °C to 80 °C, producing a lighter colour,’
says Molzahn. Malts in the darkest beers – such as stouts – are roasted
more heavily at between 95 and 105 °C, producing a wider variety and
greater number of colour compounds. Caramelisation reactions also occur
in a later stage of brewing when flavour-forming hops are boiled with wort,
the sugary liquor derived from the malt.

The trick that Miller appears to have pulled off, according to Molzahn,
is getting the coloured compounds, called melanoidins, out without extracting
too many of the flavour compounds or proteins that promote foam formation
in the beer.

Miller Clear is not the first clear alcoholic brewed beverage in the
US. Earlier this year, the Coors Brewing Company in Golden, Colorado, launched
Zima Clearmalt liquor in more than a third of American cities, although
the company insists the product is not a clear beer. ‘It has no beer characteristics,’
says the company. ‘The only similarity between a clear malt beverage and
a clear beer is that they are both malt-based beverages that are made using
brewing technology.’

Coors, the third-largest American brewer, also relies on a proprietary
filtration process to extract coloured compounds produced in the malt. It
says that Zima is ‘clear, lightly carbonated and features a unique flavour
´Ú´Ç°ù³¾³Ü±ô²¹³Ù¾±´Ç²Ô’.

But Steve Cox of the Campaign for Real Ale (CAMRA), based in St Albans,
is not persuaded. ‘You get the sense that it’s just a gimmick,’ he says.
‘It’s like brewing a beer that’s pink, or pork flavoured – you could do
it, but is it any good? It seems an entirely pointless thing to do.’

Cox believes the advent of clear beers reflects an obsession among large
US brewers with making beers as inoffensive as possible. ‘That’s why you
get lagers that get lighter and lighter and dry beers that leave no aftertaste,’
he says. They would be better advised, he believes, to learn some lessons
from the 200 to 300 small independent brewers in the US. ‘These brew beer
which is at least as good as and sometimes better than most British beers,’
he says.

Whatever the prospects for clear beers and beverages in the US, for
the moment, purists in Britain are clearly unimpressed.