Malting
Flow chart for malting and brewing Harvest
Oxygenation
Pitching Yeast strain stra in
Malting Steeping Germination Kilning
Milling
Lautering Hops
Boiling Decoction Infusion
Fermentation Lagering
Packaging Conditioning
Mashing
Barley and Malt processes
Wort production
Conversion of Wort into Beer
Commercial malting operations comprise four basic stages •
•
Barley reception: (intake, drying and storage) Steeping (critical step): even hydration of the barley kernels is key (oxygen and water temperature dependent and requires airrests)
Commercial malting operations comprise four basic stages •
•
Germination: hydrated embryo produces hormones (gibberelins which help promote synthesis of enzymes that break down B-glucan in the endosperm walls, protein and starch) that migrate to the aleuron to regulate enzyme synthesis Kilning: arrest modification of the grain, ensure survival of enzymes for mashing and introduce flavor and color characteristics and eliminate undesirable flavors
How to Malt
Floor Malting
Saladin Box
Barley 2-row and 6-row
2-row vs 6-row •
•
2-row: one kernel per node 6-row: three kernels per node (tend to have higher N content therefore a higher potential for developing enzymes however their yield of extract is lower than the 2-row variety and proportion of husk is greater than its counterpart
Anatomy of a Grain of Barley
Anatomy of a Grain of Barley •
•
•
Husk: protects the grain and is important to the brewer for filtration Endosperm: this is a non-living part of the grain which stores starch (energy source) for the growing grain. The starch is embedded in a protein matrix. There are small and large starch granules surrounded by cell walls high in β -glucan (a gummy substance which can effect filtration and haze in beer). Starch consists of long branched chains of glucose molecules. Embryo: the baby plant
Anatomy of a Grain of Barley •
•
Aleuron: generates the enzymes that degrade the starchy endosperm Scutellum: The tissue in a grass seed that lies between the embryo and the endosperm
Anatomy of a Grain of Barley
What is Malting? •
•
The controlled germination of cereal grains, in our case barley The barley is allowed to germinate (sprout) to a degree and is then dried
Unsprouted vs Sprouted Seeds
What is the Purpose of Malting? •
Break down cell walls
•
Enzyme development
•
•
Degradation of protein and starch(modification) Maillard products (ie: color and flavor) during kilning
How to Malt? •
•
This is accomplished industrially by increasing the water content of the seeds to 40-45% by soaking them for a period close to 40 hours The seeds are then drained and held at a constant temperature (60 F) for close to 5 days until they starts to sprout
How to Malt? •
•
The seeds are then slowly dried in a kiln at temperatures gradually rising to 122 F for lighter malts and 220 F for darker malts. This kiln drying takes about 30 hours Finally, the rootlets from the partially germinated seeds are removed
Physiological Events of Malting •
The key physiological event in malting include: –
–
–
Rapid and uniform germination The synthesis of hydrolytic enzymes in the scutellum and aleurone tissues surrounding the endosperm The degradation of endosperm cell walls, described as modification. - Taiz and Zeiger, Plant Physiology 4th ed.
Physiological Events of Malting
Germination of the Grain •
•
The germination process converts some starch, the seed's stored energy, into simpler sugars used in its initial growing stage. The conversion is accomplished by starchhydrolyzing enzymes (diastase enzymes) that the seed produces during this process.
Germination of the Grain •
•
The germination and drying stages capture fermentable sugars, soluble starch, and the diastase enzymes for beer brewing. Malted barley is the eventual source of the fermentable sugar consumed by the yeast. – Briggs and Hough, Malting and Brewing Science Vol.1
Gibberelins •
•
Gibberellin regulates the physiological events. It is a plant hormone produced by the germinating embryo.
Important Enzymes Produced During Malting •
•
•
Amylases (α and β –amylases): these break down the starch into simple sugars especially maltose (2 glucose molecules). Proteinases: break down the protein matrix holding the starch granules Β-glucanases: break down the β-glucans
Important Enzymes Produced During Malting
Malting
References •
•
•
•
•
1. Hough, Briggs and Stephen “Malting and Brewing Science” vol. 1, 1996 2. O`Rourke The Brewer 1994.
3. Taiz and Zeiger, Plant Physiology 4th ed., 2011 4. Palmer, John., http://www.howtobrew.com/ 5. Hough,J.S., The Biotechnology of malting and brewing. 1995
References •
Moesher, Randy., Radical Brewing. 2004
•
Noonan, Gregory., Brewing Lager Beer.1996
•
Bamforth, Charles W., Scientific Principles of Malting and Brewing. 2006
