by, kunjal patel, m.sc. microbiology

8/14/2019 By, Kunjal Patel, m.sc. Microbiology .

1/30

BEER

BY,

KUNJAL PATEL,M.Sc. MICROBIOLOGY.


2/30

ContentHistoryIngredients

Production of beer by brewingBeer stylesServingStrength of beer

Merits and demeritsConclusionReferences


3/30

History

Beer is one of the oldest human-producedbeverages since 8th millennium BC, it recorded inthe written history of Ancient Egypt andMesopotamia.

As almost any substance containingcarbohydrates, namely sugar or starch, cannaturally undergo fermentation, it is likely thatbeer-like beverages were independently inventedamong various cultures throughout the world.
http://upload.wikimedia.org/wikipedia/commons/2/20/Dutch_beers.jpg


4/30

In Europe, beer was being produced in asearly as the 7th century. By the 14th and15th centuries, beer had achieved greatpopularity, at least in part because healthepidemics made drinking beer saferthan drinking water .However it was not until the 17th

century, according to Michael Jackson,that beer took on the styles andflavours that we might recognise in thebeers of today.


5/30

Ingredients

Malted barley before roasting:Main articles: Hops, Saccharomyces cerevisiae,

Brewer's yeast, Malt, and Barley. The basic ingredients of beer are water, a fermentablestarch source, such as malted barley, and yeast.It is common for a flavouring to be added, the most

popular being hops.A mixture of starch sources may be used, with thesecondary starch source, such as corn, rice and sugar,often being termed an adjunct, especially when used a

a lower cost substitute for malted barley.


6/30

WaterBeer is composed mainly of water, which when heatedis known as brewing liquor.

The characteristics of the water have an influence onthe character of the beer.Although the effect of, and interactions between,various dissolved minerals in brewing water is complexhard wateris more suited to dark beer such as stout, while verysoftwater is more suited for brewing pale ale and palelager.


7/30

Starch source

The most common starch source is malted cereal.And among malts, barley malt is the most widely uowing to its high amylase content, a digestive enzywhich facilitates the breakdown of the starch intosugars.However, unmalted grains may be used, includingwheat,

rice, oats, and rye, and less frequently, maize andsorghum.Malt is formed from grain by soaking it in water,allowing

it to start to germinate, and then drying theerminated


8/30

Cont..Malting the grain produces the enzymes thatwill eventually convert the starches in thegrain into fermentable sugars.Different roasting times and temperatures areused to produce different colours of malt fromthe same grain.Darker malts will produce darker beers.


9/30

HopsHops have commonly been used as a bitteringagent in beer for over a thousand years.Characteristics(a) it contribute a bitterness that balances thesweetness of the malt.

(b) it also contribute aromas which range fromflowery to citrus to herbal.

(c) it have an antibiotic effect that favours the

activity of brewer's yeast over less desirablemicroorganisms.(d) the use of hops aids in "head retention.

The bitterness of commercially-brewed beers ismeasured on the International Bitterness Units

scale. While hop plants are grown by farmers.
http://en.wikipedia.org/wiki/Image:Crushed_hop.jpghttp://en.wikipedia.org/wiki/Image:Crushed_hop.jpghttp://en.wikipedia.org/wiki/Image:Crushed_hop.jpg


10/30

YEASTA specific strain of yeast is chosen depending

on the type of beer being produced, the twomain strains: 1) Ale yeast--Saccharomyces cerevisiae

2) Lager yeast-- Saccharomyces uvarum Others are Brettanomyces ,

Torulaspora delbrueckii .Yeast will metabolise the sugars extracted

from the grains, and produce alcohol andcarbon dioxide as a result.


11/30

CLARIFYING AGENTCommon examples:1) Isinglass finings obtained fromswimbladders of fish.

2) Kappa carrageenan, derived from seaweed.

3) Irish moss, a type of red alga.

4) Polyclar (artificial), and gelatin.


12/30

Brewing

Though the process of brewing beer is complex

The basic stages are1 : Mashing2 : Sparging3 : Boiling

4 : Fermentation5 : Packaging
http://en.wikipedia.org/wiki/Image:The_Brewer_designed_and_engraved_in_the_Sixteenth._Century_by_J_Amman.png


13/30

Mashing

The first phase of brewing, in which the malted grainare crushed and soaked in warm water in order tocreate a malt extract.

The mash is held at constant temperature long enoufor enzymes to convert starches into fermentable

sugars,usually about 45 to 90 minutes.

The temperature is typically held at either a singletemp.

(single step) or a series of temperatures depending o


14/30

For most mashes, a temperature between 65-67C (150-154F) is typical, with higher

temperatures yielding fuller bodied beers, andlower temperatures yielding more fermentableand lighter bodied beers.


15/30


16/30

Sparging

Water is filtered through the mash todissolve the sugars. The darker, sugar-heavyliquid is called the wort.

Typically the rinse water (sparge) is heldbetween 76-82C (170-180F) to1: keep sugars and gums from setting up.2: above 82C (180F), tannin extractioncould be a problem.


17/30

Boiling

The wort is boiled along with any remainingingredients (excluding yeast), to remove excesswater and kill any microorganisms.

The main function of boiling is to set proteins andsuch similar to cooking bread.

The hops (whole, pelleted, or extract) are added atsome stage during the boil.Bittering hops are added during the entire boil (1hour), flavoring are added between about 5 - 20minutes, and aroma hops are added at 5 minutesor less.


18/30

Fermentation The yeast is added and the beer is left to ferment.After primary fermentation, the beer may beallowed a second fermentation, which allowsfurther settling of yeast and other particulatematter which may have been introduced earlier inthe process.Some brewers may skip the secondaryfermentation and simply filter off the yeast.


19/30

Packaging At this point, the beer contains alcohol, but notmuch carbon dioxide.

The brewer has a few options to increase carbon

dioxide levels. The most common approach by large-scale brewersis force carbonation, via the direct addition of CO 2 gas to the keg or bottle.

Smaller-scale or more classically-minded brewerswill add extra sugar or a small amount of newlyfermenting wort to the final vessel, resulting in ashort refermentation known as "cask-" or "bottleconditioning" .

After brewing, the beer is usually a finished product.At this oint the beer is ke ed casked bottled or


20/30

BEER STYLESStyles of beer are:-

1) ALE

Beers which use a fast acting yeast whichleaves behind residual sugars are termed ales. 2) LAGER

Beers which use a slower and longeracting yeast which removes most of the sugarsleaving a clean and dry beer are termed lagers.


21/30

ALEAle is typically fermented attemperatures between 15 and 24C(60 and 75F).At these temperatures, yeastproduces significant amounts of esters and other secondary flavourand aroma products, and the result is

often a beer with slightly "fruity"compounds resembling but notlimited to apple, pear, pineapple,banana, plum, or prune.

Typical ales have a sweeter, fullerbody than lagers


22/30

LAGERLager is the English name for bottom fermenting beersof Central European OriginLager name comes from the germen lagern to store

Lager yeast is a bottom-fermenting yeast, andtypically undergoes primary fermentation at 7-12 C(45-55 F)

Then is given a long secondary fermentation at 0-4 C(32-40 F) During the secondary stage, the lager clears

and mellows. The cooler conditions also inhibit the naturalproduction of esters and other byproducts, resulting ina "crisper" tasting beer.
http://en.wikipedia.org/wiki/Image:Keg_Fonts.jpghttp://en.wikipedia.org/wiki/Image:GravityTap.jpg


23/30

ServingDraught beer from a pressurized keg is usedaround the world. A metal keg is pressurized withcarbon dioxide (CO 2) gas which drives the beer to

the dispensing tap.Some beers, notably stouts, and"Smooth" bitters, such as Boddingtons, may beserved with a nitrogen/carbon dioxide mixture.Nitrogen has fine bubbles, producing a dense headand a creamy mouthfeel.Cask ales are unfiltered and unpasteurised.It is allowed to cool to cellar temperature(typically around 13C / 55.4F)
http://en.wikipedia.org/wiki/Image:Keg_Fonts.jpghttp://en.wikipedia.org/wiki/Image:GravityTap.jpg


24/30

Bottles and cansMost beers are filtered before bottling. But soare bottle conditioned.Bottle conditioned beers are unfiltered andunpasteurised. It is usually recommended thathe beer is poured slowly, leaving any yeastsediment at the bottom of the bottle. Howevesome drinkers prefer to pour in the yeast, an

this practice is customary with wheat beers.

A lot of beer is sold in beer cans. People eithedrink from the can or pour the beer into a gla


25/30

Strength of beers The alcohol content of beers varies by local custom.British ales average around 4% above, while Belgianbeers tend to average 8% above. The strength of thetypical global pale lager is 5% above.

Some brewers use champagne yeasts to artificiallyincrease the alcohol content of their beers. The strongest beer sold in Britain was Dogfish Head'sWorld Wide Stout , a 21% aboveIn Japan in 2005, the Hakusekikan Beer Restaurant

sold an eisbock, strengthened through freezing,believed to be 28% above. The beer that is considered to be the strongest yetmade is Hair of the Dog's Dave - a 29% above barleywine made in 1994.


26/30

Merits of beerBeer contains alcohol which has a number of health risks and benefitsNutritionally, beer can contain significant

amounts of magnesium, selenium, potassium,phosphorus, biotin, and B vitamins. Typically,the darker the brew, the more nutrient dense.A 2005 Japanese study found that non-

alcoholic beer may possess strong anti-cancerpropertiesOverconsumption of alcohol is a problematicwith improper exercise and overconsumption

of carbohydrates than the product itself.


27/30


28/30

ConclusionBeers having large number of roles in healthstrengththough its have a large number of affects.So beer is not to be consumed by teenager.In Gujarat, alcoholism is a banned so pleasenot to be consumed.


29/30

Referenceswww.wikipedia.com

www.google.com

www.googleimages.com
http://www.wikipedia.com/http://www.google.com/http://www.googleimages.com/http://www.googleimages.com/http://www.google.com/http://www.wikipedia.com/


30/30

by, kunjal patel, m.sc. microbiology

Documents