Presentation is loading. Please wait.

Presentation is loading. Please wait.

By Dmitry Liskin Norfolk, VA October 2012

Similar presentations

Presentation on theme: "By Dmitry Liskin Norfolk, VA October 2012"— Presentation transcript:

1 By Dmitry Liskin Norfolk, VA October 2012
Biochemistry of Beer

2 What is Beer? According to Rheinheitsgebot (1516) beer should only contain: Water Barley Hops Yeast was discovered in 1800 by L. Pasteur

3 origin of beer Beer-like beverages appeared around 10,000 BC
First evidence points at Mesopotamia region Is said to be responsible for development of agriculture

4 water Hardness Other ions Carbonate – temporary Sulfate – permanent
Gave birth to beers with malty, smooth finish Munich, Dublin, London, St.Louis, Milwaukee Sulfate – permanent Bitter, pale beers Burton-on-Trent Other ions zinc, copper are necessary for fermentation Iron, manganese and chloride will cause flavor problems

5 barley Malt: barley that has been sprouted and dried Color Aroma
Golden to black Aroma Bready, malty, nutty, toasty, roasty Flavor Caramel, toffee, molasses, coffee These characteristics develop due to non-enzymatic browning reactions

6 Caramelization Thermal decomposition of sugar, pyrolysis
110 oC – 180 oC Low-moisture Produces a variety of products

7 Maillard reactions Reaction between amino acid and sugar
48 oC – 230 oC

8 hops Beer preservation Bitterness Flavor Aroma

9 yeast Brewers’ best kept secret Converts fermentable sugars to alcohol
Top fermenting – ale; bottom - lager Contributes to flavor with other byproducts Fusel alcohols Esters Aldehydes

10 Classic Beer styles Bitters and Pale ale Stout Scottish ale
India Pale ale Lager

11 Bitter and Pale Ale The beer of an Empire (1702 – 1714)
Use of coal gave birth to pale malt Firm hop bitterness Low hop character Touch of caramel from malt (bitters) Light fruity character from yeast About 5% alcohol

12 Stout Dark beer with roasty character
Refreshing low alcohol to warming high gravity beers Dry stout Sweet stout Oatmeal stout Imperial stout

13 Scottish ale Malt sweetness, smoky Clean finish Low bitterness
Wide range of alcohol levels 60/-, 70/- and 80/-

14 India pale ale (IPA) Bitter, hoppy ale Crisp finish
Malty, some caramel flavor Moderately strong (5% - 7.5% alcohol)

15 lager Malt focused beers Low hop character 4.4% – 5.4% alcohol
Clean finish Most food friendly style

16 Making of beer - mashing
Base malt with specialty grains Mashing Hydration of malt Gelatinization of starches Release of natural enzymes Conversion of starch to fermentable sugars

17 Enzymatic activity Starch conversion (60 oC – 75 oC) Protein rest
Alpha-amylase Beta-amylase Limit-dextrinase Alpha-glucosidase Protein rest Proteases peptidases

18 Boiling the wort Beer clarity Hop additions
The hot break – protein coagulation The cold break – protein coagulation Hop additions Bitterness – min Hop flavor – 20 min Hop aroma – 5 min or dryhopping

19 Alpha acid isomerization
Alpha acids = Bitterness of beer Humulone Cohumulone Adhumulone Measured by IBU’s (International Bittering Unit) 1 IBU = 1 mg alpha acid per 1 L

20 Flavor and aroma compounds
Myrcene – pungent Humulene – delicate and refined Caryophyllene oxide – herbal/spicy

21 fermentation Beer is born when yeast is pitched Yeast characteristics
Type – Lager, Ale, Weizen Flavor – malty, fruity, woody, etc. Attenuation – degree of fermentation Temperature – impacts flavor Flocculation – precipitation of yeast Sugar, oxygen, nitrogen and minerals are needed

22 Yeast at work Adaptation Attenuation Conditioning High growth
Aerobic process A few hours Attenuation Production of alcohol Anaerobic process Fermentation of simple sugars 4 – 10 days Conditioning Conversion of byproducts to ethanol Flocculation

23 Yeast byproducts Diacetyl and pentadione – buttery flavor
Acetaldehyde – green apple aroma and flavor Fusel alcohols – oxidation to esters; fruity aroma These byproducts will be metabolized during conditioning stage

24 Finished product Water Malt Hops Yeast
Hardness affects mash pH and taste Malt Color, flavor, aroma and body Hops Preservation Bitterness, flavor, aroma Yeast Alcohol, flavor, aroma, clarity Combination of these factors gives the finished product Complex flavors are desired while complicated ones to be avoided

25 acknowledgements Referenced literature O’Connor Brewery
Randy Mosher “Radical Brewing” John Palmer “How to Brew” Ray Daniels “Designing Great Beers” Jamil Zainasheff and John Palmer “Brewing Classic Styles” BYO “Brew Your Own” magazine O’Connor Brewery Christopher Newport University department of Molecular Biology and Chemistry Fellow brewers

Download ppt "By Dmitry Liskin Norfolk, VA October 2012"

Similar presentations

Ads by Google