The History, Science, and Engineering of

Brewing

Brief History• Evidence of beers created over 5,000 years ago

• Beer has been an integral part of society• Sustenance: Low alcohol (1%), high gravity beers

• Energy storage• Liquid meal – Egyptians, Colonists

• Safe water supply• Sterilization inherent of making beer

• Hops and Boiling• I.P.A’s

• Religion and Health• Blood of Christ – Church Brewed• Monastic Beers• Anesthetic - Surgery

• Today – 39 Billion gallons of beer brewed annually

2

Beer: Unit Operations• Barley is grown, harvested, and dried (Malting)

• Malt is milled and steeped in water to create sweet wort (Mashing)

• Sweet Wort is boiled and hops are added to create bitter wort (Boiling)

• Wort is chilled to fermentation temperature and yeast added

• Fermentation takes 2-6 weeks depending on beer style yeast

• Wort has now become beer. It is filtered, carbonated, and packaged

• Shipped and Consumed

3

Barley Harvest and Malting

4

Specialty Malts

5

Milling

Milling: Husk crushed to increase surface area to improve saccharification

6

Mashing

7

Mashing: Grain to Water ratio (Grist Ratio) and time of mash determines extract efficiency

Mashing Chemistry

• Starches given, sugars needed– Enzymes are found naturally in grain

• Generate needed fermentable sugars from starches (saccharification)

Alpha-AmylaseBeta Amylase

8

EnzymesEnzyme Optimum

Temperature

Range

Working pH

Range

Function

Phytase 86-126°F 5.0-5.5 Lowers the mash pH. No longer used.

Debranching (var.)

95-113°F 5.0-5.8 Solubilization of starches.

Beta Glucanase 95-113°F 4.5-5.5 Best gum breaking rest.

Peptidase 113-131°F 4.6-5.3 Produces Free Amino Nitrogen (FAN).

Protease 113-131°F 4.6-5.3 Breaks up large proteins that form haze.

Beta Amylase 131-150°F 5.0-5.5 Produces maltose.

Alpha Amylase 154-162°F 5.3-5.7 Produces a variety of sugars, including maltose.

Major Enzyme Groups and Functions

9

Boiling Kettle• Wort is boiled for an hour

• Energy Intensive

• Hops are added:• Bittering • Flavoring• Aromatic

10

Chilling/Aerating• Wort is cooled to fermentation temperature

• Heat Exchangers

• Oxygen solubilized into wort• Allows yeast to perform aerobic respiration to grow and

multiply

11

Fermentation

• Wort pumped to fermentation tank• Yeast is added

• Wort maintained chilled• Fermentation exothermic

• more heat exchangers

• 2-6 week wait• Gravity Checked

12

Fermentation

13

Yeast Fermenter. Imperial Chemical Industries, Billingham,UKVolume: 98,000 Ft^3

Filtration/Carbonation/Bottling

• “Green” Beer Filtered• Diatomaceous Earth

• Brightening Tank• Chilling to precipitate out proteins

• Carbonation• Bottling/Kegging• Shipped!

14

Summary

Malting

KilnMill Mash Tun

Boiling Kettle

FermentationFiltrationCarbonationPackaging

Barley Water

HopsFinnings

Salts

Spent GrainsWater

Solids YeastCO2

YeastO2

Hops

Trub

CO2

Bottles/Cans/ Kegs

Moisture Dust

15

What about Wastes?• Spent Grain/Trub

• Fertilizers/Cow Feed

• CO2 Production during Fermentation• Capture and use for carbonation?

• Spent Yeast• Protein Powder• Adsorbent for waste in another industry

16

Q & A?

17