1. ENZYMES – UNLOCK YOUR BREWING POTENTIAL
Nicholas J Brading
Master Brewer, Murphy & Son Ltd

2. ENZYMES
An enzyme is one of Nature’s biocatalysts, life is not possible without them.
They are found in the living cells of all organisms; they are proteins with very high specificity.
Enzymes used in industry are all extracted from living organisms so are therefore natural.

3. ENZYMES Enzyme activity depends on a substratepH
Temperature
Time
Dose rate
Small quantities will work on large amounts of substrate.

4. ENZYMES

5. ENZYMES Barley malt contains: And the enzymes: Starch Protein
Beta Glucans and Gums
Polyphenol in husk
α- and β-amylases
Proteases
Glucanases
Phytase
Cellulase, hemicellulase, dextrinase, etc.

6. ENZYMES
Well modified malt:
Undermodified malt:

7. ENZYMES Amyloglucosidase (AMG) Brewers Clarex (Clarity)
AcetoLactateDeCarboxylase (ALDC)

8. ENZYMES – Amyloglucosidase (AMG)
Starch is a polymer made up of glucose units.
Glucose is also called Dextrose in some industries. The carbon atoms
are numbered
thus:

9. ENZYMES (AMG) 2 Structures in Starch Amylose α 1→4 links
Amylopectin α 1→4 & α 1→6 links

10. ENZYMES (AMG) Amyloglucosidase or AMG Source: Aspergillus niger
Hydrolyses α-1,4 and α-1,6 linkages (from non-reducing end)
Glucose units are the end product (fermentable)
pH optimum 4.0 +/- 0.2
Temperature optimum 75°C
Inactivated by pasteurisation or boiling
Ideal for low calorie & dry beers (S.G. < 1.000)
Dose rate 3 – 8g/hl wort into the mash

11. ENZYMES - Proteases
The Proteins in Barley have been classified into 4 groups:
Albumins soluble in H2O (10% of total protein)
Globulins soluble in dilute salt solution (5% of total proteins)
Hordeins soluble in alcohol / H2O mixtures
Glutelins soluble in dilute acid or alkali
Hordeins & Glutelins account for over 85% of proteins.
Hordeins & Globulins are termed storage proteins
(act as reservoirs of nitrogen for the embryo)
Albumins & Glutelins are structural proteins & enzymes

12. 50% of Hordein is made up from the
ENZYMES - Proteases
50% of Hordein is made up from the
amino acids
Proline & Glutamine

13. ENZYMES - Proteases
Most hydrolysis occurs during germination in the Malthouse
Some hydrolysis occurs in the mashing process at below 50°C
Hydrolysis involves 2 classes of enzymes:
Endo- proteases to produce peptides
Synthesised during germination
There at least 40 such endo-proteases
Intolerant to heat above 50°C – 55°C
2 Exo-proteases to produce amino acids
Heat-stable; Normally not limiting

14. ENZYMES - Proteases Endoprotease Exoproteases Amino-acid Amino-acid
NH2 – CH – CO – NH – CH – CO – NH – CH – CO – NH – CH – COOH
Amino-acid
Amino-acid
Endoprotease
Aminopeptidase
Carboxypeptidase
Exoproteases

15. Proline in a Peptide Chain
Prolines in a peptide adopt only a limited number of  and  angles. As a consequence proline rich peptides are severely restricted in their conformational freedom resulting in a conformation that is fairly rigid and extended.

16. ENZYMES - Proteases Brewers Clarex (Clarity)
Proline specific endo-protease
Source: self-cloned strain of Aspergillus niger from DSM
Hydrolyses proline groups from the peptide chain
pH optimum 5.0 +/- 0.1
Temperature optimum 20° +/- 3°C
Delays chill haze formation & reduces gluten content
Inactivated by pasteurisation or substrate removal
Dose rate 0.5 – 3g/hl cold wort into the FV

17. ENZYMES – Diacetyl AcetoLactateDeCarboxylase (ALDC)
During the yeast growth phase (lag phase) of early fermentation, yeast needs to produce valine.
Acetolactate is an intermediary product in this process; cell wall leakage into the wort.
Contact with oxygen in the wort → Diacetyl
Butterscotch, toffee, unpleasant off-flavour

18. ENZYMES - Diacetyl

19. ENZYMES - Diacetyl AcetoLactateDeCarboxylase (ALDC)
Carboxypeptidase action
Source: submerged culture of Bacillus subtillis
Hydrolyses acetolactate to acetoin, no flavour
pH optimum 4.0 +/- 0.2
Temperature optimum 25° - 40°C
Dose rate 1.0 – 5.0g/hl cold wort into the FV start of fermentation
Dose rate 2.5 – 10g/hl into cold dry-hopped beer to prevent “hop creep”