On food and cooking the science and lore of the kitchen ( PDFDrive ) 1406

betweenthesugarmaltoseandtheaminoacid
proline. And it begins the process of
clarifying the brew by coagulating large
proteins and causing them to bind with
tannins from the barley hulls, form large
masses, and precipitate out of the solution.
Whenboilingisfinished,thewortisstrained,
thencooledandaerated.
OPPOSITE: Making beer. Beer is made in two

basicways.Alesarefermentedinlessthana
weekatawarmtemperatureandmaturedfor
days, while lagers are fermented for more
than a week at a cold temperature and
maturedforweeks.
Fermentation With boiling, the brewer has
finished transforming the bland barley grain
into a rich, sweet liquid. Now the yeast cells
transform this liquid into beer, which is far
lesssweet,butmorecomplexinflavor.
Therearetwobasicmethodsfor
fermentingbeer,andtheyproducedistinctive


results.Oneisrapidfermentationatahigh
temperaturewithaleyeasts(strainsof
Saccharomycescerevisiae)thatclump
together,trapthecarbondioxidegasthatthey
produce,andrisetothewortsurface.The
otherisslowfermentationatalow
temperaturewithlageryeasts(Saccharomyces

uvarumorcarlsbergensis)thatremain
submergedinthewortandfalltothebottom
whenfermentationisover.Theseareoften
called“top”and“bottom”fermentations.
Topfermentationisusuallycarriedoutat
between64and77ºF/18–25ºCandtakestwo
tosevendays,duringwhichtheyeastyfoamis
skimmedoffseveraltimes.Becausetheyeast
layeratthetophasagoodsupplyofoxygen
andisinevitablycontaminatedbyother
airbornemicrobes,includinglactic-acid
bacteria,top-fermentedbeersareoften
relativelyacidicandstronginflavor.Bottom
fermentationgoesonatdistinctlylower
temperatures,43to50ºF/6–10ºC,takessixto