Lecture #1 and #2 beer and the brewing process. alcohol -What is it? a class of molecules that have an –OH group methanol- 1 carbon ethanol- 2 carbons.

lecture #1 and #2

beer and the brewing process

alcohol -What is it?

a class of molecules that have an –OH group

methanol- 1 carbonethanol- 2 carbonspropanol- 3 carbons butanol- 4 carbonspentanol- 5 carbons

alcohol -Where does it come from?

aerobic respiration - requires oxygen - 36 ATP per glucose molecule - low energy waste products, H2O and CO2

alcoholic fermentation

lactic acid fermentation

anaerobic respiration

fundamental metabolic processes:extracting energy from sugar

glucose


anaerobic respiration = fermentation

- extraction of energy from glucose without oxygen

- only 2 ATP per glucose molecule

- very inefficient, high energy waste products

- lactic acid

- ethanol


We’re only concerned with alcoholic fermentation

- many fungi and bacteria can perform alcoholic fermentation; fairly common amongst microorganisms

- Saccharomyces cerevisiae brewer’s and baker’s yeast

water + sugar + yeast + time = alcoholic beverage

- alcohol is a byproduct of yeast metabolism, it’s a waste product, it’s yeast poop

alcoholic beverages

the source of sugar, the process, other ingredients, and geographic origin are used to classify types of alcoholic beverages

In other words, why are there so many types of alcoholicbeverages?

What makes beer beer?

alcoholic beverages -Sugar source

beer

wine

sake

mead

cider

pulque

masato

chicha

cyser

birch beer

grains

grapes, fruit

rice

honey

apples

agave sap

manioc root

corn

honey and apples

birch sap

whiskey, vodka, gin

brandy, grappa

awamori

calvados, apple jack

distilled mead

tequila

??

bourbon

alcoholic beverages -Process

beer

wine

sake

mead

cider

pulque

masato

chicha

cyser

birch beer

grains

grapes, fruit

rice

honey

apples

agave sap

manioc root

corn

honey and apples

birch sap

whiskey, vodka, gin

brandy, grappa

awamori

calvados

distilled mead

tequila

??

bourbon

alcoholic beverages -Process

the process

- wines typically have nothing added to them, just juice; not cooked, but cider too

- sake is made with different yeasts than beer, different process

- chicha is made with different yeasts than beer, different process

alcoholic beverages -History

geographical factors:

- where each type of sugar source was first domesticated

- degree of isolation

- local names/traditions lead to divergence of beverages

alcoholic beverages

today, beer is usually made with four primary ingredients:

(1) water

(2) malted barley

(3) hops

(4) yeast

Modern beer also has a very particular process of production

the beer we know today has only been around since the mid 1600s

brewing beer

cultivatemaltmillmashspargeboilhopfinecooloxygenatepitchfermentagefinefilterpackageenjoy

HISTORICAL DISCLAIMER

brewing beer -Cultivating

What are grains?

- Angiosperm, grasses, Poaceae, (flowering plants)

- the fruit of the grass, but starchy not sugary

- Hordeum vulgare, barley

brewing beer -Cultivating

other grains used in brewing:

- wheat

- corn

- rice

- rye

- oats

brewing beer -Malting

but yeast can’t use starch to live, thus they can’t makealcohol from starch

- this is not an issue in wine making, why?

- a big difference in process


what is starch?


need to convert the starch to sugar so that the yeast can usethe energy stored in the starch to make alcohol

- what is fruit for? why do plants have fruit? why do

grasses have grains?


no living thing (or very few living things) can use starch directly to get energy

- most living things need to convert starch to sugar first

- yeast can’t do it

- some fungus can

- plants can

- humans can


brewers borrow the plant’s ability to convert starch to sugarby tricking them into thinking they’re growing

this is malting

soaksproutspread and germinatekiln

α-amylaseβ-amylase

also in human saliva


malting is also where much of a beer’s character is determined

- type of barley used

- 2 row vs 6 row- color, protein- American- Canadian- English -Maris Otter- Scottish –Golden Promise –terroir? - German- Belgian

- malting method

- floor malted- machine malted- kilning fuel –peat, wood smoke


kilning

- temperature

- length

- moisture content

types of malt

- base malt- biscuit- Vienna- Munich- aromatic- crystal- chocolate- black patent- roasted barley

brewing beer -Milling

need to expose the starch

don’t want to pulverize the grains, need to keep the husks intact for the sparge or else big trouble –peated malt

brewing beer -Mashing

converting starch to sugar by activating a suite of enzymes that were created by malting the grain

mix milled grains with water in a mash tun

water/grain ratio, temperature, water chemistry all affect how the starch is converted

low temps, 140°F = lots of glucose

high temps, 160°F = lots of complex sugars, dextrins

starch

glucose

maltose

dextrin


glucose

140°F

150°F

160°F

+


some beers use unmalted grains in the mash such as corn, ricewheat, the big 3 use a lot of these adjuncts

- how could this be a problem? how to remedy the problem?

brewing beer -Sparging

how to separate the crushed grain from the sweet liquid, the wort, that will become beer?

- straws

- grain bed, husks

lauter tun (usually mash tuntoo)


recirculation –recirculate the wort until it is clear

parti gyle –do one mash, then drain all the wort off, add more hot water, do another mash, drain all the wort, continue until all sugars are gone

- usually results in two or three smaller batches of beer that range from strong to medium to weak

sparging –do one mash, begin to drain the wort off and as the wort level falls, add hot water, sparge water, to rinse the sugars from the grains, continue until all sugars are rinsed

- usually get one big batch of beer that is one strength, weaker than first runnings of parti gyle but stronger than second runnings


What do I mean by strong and weak wort?

original gravity –the density of the wort before fermentation determined by how much sugar is dissolved in the wort

high gravity = lots of sugar = high density

lots of sugar = potential for lots of alcohol

brewing beer -Boiling

wort –the clear, sugary liquid that is collected during run off, also called sweet wort

collected in the boil kettle or just kettle

why boil?

- “sterilize” wort

- coagulate proteins

- concentrate sugars

- extract hop oils

brewing beer -Hopping

Humulus lupulus

a tall, non-woody vine that dies back to the ground every winter, perennial, Cannabaceae family, sister genus to hemp

female flowers produce cones that bear lupulin glands which contain many different oils that contribute bitterness, flavor,and aroma to beer, also bacteriostatic, used to balance sweetness of malt

must be boiled vigorously to extract the oils



many different varieties, typically grouped by region of origin, American hops most distinct

- England

- Fuggles - East Kent Goldings - Target - Challenger

- Germany

- Spalt - Tettnanger

- Hallertau

- United States

- Cascade - Simcoe - Chinook - Magnum

- Czech Republic

- Saaz


hops are just one type of spice

others still used today

- orange peel- coriander

more historical

- rosemary- spruce tips- myrica gale- wormwood- mints

brewing beer -Fining

fining –the addition of material to beer or wort that aids in the clarification of the wort and beer

during the boil, carrageen in Irish Moss helps pull proteins out of solution

brewing beer -Cooling

brewing beer -Oxygenating

even though fermentation is an anaerobic process, we want the yeast population to be large enough and strong enough to havea healthy fermentation

brewing beer -Pitching

pitching –the addition of yeast to the cooled wort, also called bitter wort now

until very recently, 1940sand 50s in England, mixedcultures of yeast were pitched

pure culture fermentation, only one type of yeast, wasnot adopted until 1890s in Europe, now almost universal

1/1000 of a millimeter

yeast

Ascomycota

fungi

Basidiomycota

brewing beer -Yeast and fermentation


AscomycotaBasidomycota


fermentation –the period of time from pitching to complete attenuation (also the biochemical process that makes ATP without oxygen)

attenuation –the degree to which the yeast convert sugar to alcohol and CO2

original gravity –density of the bitter wort before pitching, many sugars dissolved in the wort

final gravity –density of beer after fermentation is complete, depends on yeast strain, mash

temps


stages of fermentation

primary fermentation -where vast majority of attenuation occurs, 3-20 days

lag phase –yeast are acclimating to wort, little obvious activity, 2-24 hours

aerobic phase -yeast grow very rapidly, population increases exponentially, consumes much of the sugar, much attenuation occurs here, consumes oxygen, obvious activity, 1-5 days

anaerobic phase –yeast begin to ferment the sugars left in the wort, activity slows, 1-15 days


secondary fermentation –to be covered in aging section


Saccharomyces cerevisiae

sacchar- sugar (saccharide, saccharine)

myces- fungus (ancient Greek)

ceres- Greek goddess of agriculture? (cereal)

Saccharomyces carlbergensis

Carlsberg- Danish city where lager species was

first isolated

Saccharomyces cerevisiae -ale yeast –warm fermentation, between 65-90°F (avg 70°F), typically more character than lager strains, less attenuative, short fermentation and aging, as short as 5 days from grain to glass, top fermentation


S. uvarum (S. carlbergensis) –lager yeast –cool fermentation, between 48-55°F, typically cleaner than ale strains, more attenuative, long fermentation and aging, primary: 20 days, secondary or lagering period, at least 14 days, bottom fermentation


many different strains within each species, 1000s of strains

- in addition to alcohol and CO2, different strains contribute different flavors and aroma

- Belgian strains: lots of character, fruity, clove, can be very attenuative even though they’re ale strains

- English strains: lots of character, fruity, bready, not attenuative, ale strains

- German strains: mostly lager strains, clean, attenuative

- American strains: both ales and lager, typically clean



spontaneous fermentation –no yeast is added “by hand”; Belgian lambic style beer; many different

microorganisms


brewing beer -Aging

after fermentation, beer is generally racked from one vessel to another, from the primary fermenters to the aging tanks

beer is aged for a couple reasons

- to complete attenuation

- *for proper flavor development, yeast reabsorb certain molecules, chemical reactions occur etc.*

- for the beer to clear

aging also known as secondary fermentation

some ales not aged at all, Upland Wheat, most aged only 1-2 weeks, very strong ales aged up to a year or more

brewing beer -Aging

brewing beer -Aging

lagering –a long period of cold aging that is normally required when using a lager strain, lager = to store

lagering takes at least 2 weeks, usually a month to 6 weeks, the stronger the beer, the longer the aging

brewing beer -Fining

at this stage, finings are added to encourage the yeast to drop out of suspension, but also proteins and other large,haze forming molecules, both a physical and electrical process

isinglass and gelatin are popular finings, some strict vegetarians object to its use, swim bladders and bones etc.

usually used in British breweries, synthetics are becoming more and more popular such as polyclar and DE

brewing beer -Filtering

beer is typically filtered immediately before packaging

filtering removes all yeast and other microorganisms, can also remove proteins and other large molecules

has an effect on packaging because filtering impactsstability of the product, when stripped of large molecules, there can’t be much chemical activity in thebeer and thus it can’t change much and of course with everything living having been stripped out, nothingcan grow and spoil the beer that way

brewing beer -Packaging

cansbottleskegscasks

How to get the gas into the beer?

artificial carbonation –filter the beer and forcibly inject CO2 then package

natural carbonation

- do not filter, add extra sugar or actively fermenting wort, and put a cap on it

- filter, add some sugar AND yeast or actively fermenting wort (Sierra Nevada)

brewing beer -enjoy responsibly

Lecture #1 and #2 beer and the brewing process. alcohol -What is it? a class of molecules that have an –OH group methanol- 1 carbon ethanol- 2 carbons.

Documents

beer beer

brewing process slide

different process slide

barley slide

bourbon slide

divergence of beverages

sugar glucose slide

yeast modern beer