Sugar Chemistry in Beer (and Candi Sugar)

This was a presentation given by Jacques Marais in the October 2020 LAB meeting

Transcript

1. Sugar Chemistry in Beer (and Candi sugar) Jacques Marais – 05 Oct 2020
2. Introduction • Types of sugars • Yeast fermentation of sugar • Brewing beer with Sugars • Reactions involving sugar • Maillard reactions • Vs. Caramelisation • Reaction and products • Some biochemistry • What is Candi sugar? • Making Inverted sugar • Making Candi sugar • Process • Recipes • Variations and Beer styles
3. Types of Sugars Sugar Wort % Carbohydrate Characteristics Glucose 10-25% Monosaccharide C6 H12 O6 aka. Dextrose, Blood sugar, Corn sugar Fructose 2-4% Monosaccharide C6 H12 O6 Isomer of Glucose. Found in fruit (wine) Sucrose* 2-5% Disaccharide: Glucose + Fructose Found in cane or beet. Table or cane sugar Maltose 50-70% Disaccharide: Glucose X 2 Found in malted grains Maltotriose 10-20% Polysaccharide: Glucose X 3 Fully/Partially fermentable Dextrins 10-25% All larger Polysaccharides Various complexities. Mostly Unfermentable Galactose 0% Monosaccharide C6 H12 O6 Found in diary, not beer Lactose 0% Disaccharide: Glucose + Galactose Found in milk. Unfermentable Carbohydrate: Carbon based molecule: CM (H2 O)N Polysaccharides are chains of monosaccharides with glycosidic bonds • Storage: Glycogen (animals), Starch (plants) • Structural: Chitin, Cellulose, Peptidoglycan *Non-reducing sugar: Missing free aldehyde (-CHO) or ketone (=O) group and cannot form open chains
4. Yeast fermentation of sugars • Chemistry • Monosaccharide (C6 H12 O6 ) → Ethanol (2 C2 H5 OH) + Carbon Dioxide (2 CO2 ) + energy • Order of yeast fermentation of sugars 1. Sucrose → Glucose and Fructose (uses Invertase enzyme outside cell wall) 2. Glucose then Fructose (metabolised inside cell wall) 3. Maltose (uses Maltase enzyme inside cell wall) 4. Maltotriose: fermentability varies by yeast strain • Yeast characteristics • Diastaticus: Yeast has STA(1-3) gene: uses Glucoamalyse enzyme to ferment some dextrins • Glucophilic: Ferments all monosaccharides first before switching to larger sugars • E.g. Duvel and DuPont strains • Too many monosaccharides/disaccharides => Difficult maltose fermentation (yeast stress) • Brettanomyces and pediococcus ferment larger dextrins
5. Yeast fermentation of sugars Remaining sugars = dextrins: only sweet, but add body Malt flavour and aroma is derived from other compounds derived from biochemical reactions
6. Add Sugar directly in Beer? Why use sugar in beer? • Increase the alcohol • Lighten the body • Interesting flavours and aromas • Priming How to Add sugar to beer? • Add to the boil: easy, no sanitation • After/During primary: • Stronger maltose fermentation • Less yeast stress • OG > 1.060 or sugar > 15% • Secondary: if flavour is subtle • Bottling: carbonation (and flavour)
7. Sugars used in Brewing Brewing Sugar Composition Characteristic Dextrose 95% Glucose, 5% moisture Highly fermentable, Sweeter and softer Table Sugar 100% Sucrose From cane or beet Malt extract & DME Similar to wort Various types available Maltodextrin 95% Dextrins (?) Partially fermentable, adds body Lactose 100% Lactose Unfermentable, adds body and sweetness Honey 35% Fructose, 30% Glucose, 20% Moisture, 15% other Contains wild yeast and bacteria Maple syrup 85-95% Sucrose Subtle flavour Molasses* 100% sucrose Includes unrefined by-product of cane sugar Golden Syrup 40% Sucrose, 60% Glucose/Fructose Partially inverted Sucrose Treacle 40% Sucrose, 60% Glucose/Fructose Partially inverted Molasses Candi Sugar Sucrose, Glucose, Fructose Maillard reactions and Caramelisation * Includes Brown sugar, Piloncillo, Demerara, Turbinado, Muscovado, black strap Other: Caramel, essentia bina (used in old porters), jaggery (palm sugar), agave nectar, various syrups
8. Reactions involving Sugar Inversion • Converts Sucrose into Glucose and Fructose (=Inverted sugar) through hydrolysis (needs water) • Faster with higher temperatures and lower pH • Also occurs enzymatically (Invertase) Maillard reactions • Non-enzymatic reaction between amino acids and reducing sugars • First described by Louse-Camille Maillard in 1912 • Creates 1000s of new compounds e.g. Melanoidin • Gives food and beer it’s colour and flavour: steak, cookies, biscuits, e.g. doppelbock Caramelisation • Pyrolytic process: breakdown and oxidation of reducing sugar then recreation of larger chemicals • Dehydration, Condensation, Isomerisation, Fragmentation, Polymerisation, Cyclisation • Overlaps with Maillard reactions • Flavours: caramel, toffee, chocolate, roasted, e.g. stout, wee heavy
9. Maillard reactions in beer • Amino acids • Molecule with Amine (NH2) and Carboxyl (COOH) group • Building blocks of proteins • 19 types in beer - Lysine and Theonine most common • Needed for healthy fermentation • Sugars • Fructose (Ketose) faster than Glucose (Aldose) • Sucrose must invert first • Faster reactions with: • Higher temperature • Higher pH • Higher concentration of ingredients • Less water, but needs some • Iron and Copper catalysts • Melanoidins (most important result) • Gives colour and toasty-sweet flavour to beer • Oxidises when hot, Anti-oxidising when cooler • Catalyst for aldehyde and higher alcohols formation • Reaction in turn lowers the pH Maillard reactions are poorly understood
10. Maillard reactions Stage I: A – Sugar-amine condensation B – Amadori rearrangement Stage II: C – Sugar dehydration D – Sugar fragmentation (unstable) E – Amino acid degradation (Strecker) Stage III: F – Aldol condensation G – Aldehyde-amine condensation • Amadori/Heyns Rearrangement Products (ARP/HRP) • Isomerisation or rearrangement of • Aldose: contains aldehyde –CH=O e.g. Glucose • Ketose: contains ketone group C=O e.g. Fructose • Stable, irreversible, high/low pH, varying temperatures • Furfural + HMF and Reductones • Amino Acid degrades to Strecker Aldehydes • Requires high pH • Heterocyclical derivatives • Carbon ring with N, S, O or others • N-free polymers: poorly understood <=> Caramelisation <=> <=> <=> • Melanoidins: • Brown complex nitrogenous polymers • Difficult to isolate and distinguish • Faster formation with high pH <=> <=> <=> https://www.brewersjournal.ca/2017/05/18/science-malliard-reaction/
11. Aldehydes in beer
12. Maillard reactions vs. Caramelisation Characteristic Maillard reactions Caramelisation Reaction Sugars react with amino acids Sugars breaking and reforming Flavours Bready, sweet, fruity, toasty, nutty, biscuits Caramel, nutty, coffee, toffee, chocolate, roasty Temperatures 0-55 ͦC – months-years 55-100 ͦC – hours-days 110-135 - hours 135-165 ͦC – minutes >165 ͦC – Caramelisation too fast Happens in seconds-minutes at temperatures: Fructose: >110 ͦC Sucrose, Glucose: >160 ͦC Maltose: >180 ͦC Lactose: > 200 ͦC pH Faster and more complex at higher pH (>7) Faster at higher OR lower pH ≠ 7 Resulting Compounds Melanoidins, Strecker aldehydes, Furfural, Heterocyclical compound derivatives, Other complex polymers Caramelens, Esters, Maltol (toasty), Diacetyl (butter), O- Heterocyclical derivatives, Lactones (rum) Oxidation Oxidising when hot, antioxidant when cool Mixed, but generally oxidising over time Effect on Colour Lots of browning from few reactions Faster browning at higher temperatures
13. Faults: Malt & Oxidation
14. Resulting flavours and aromas in beer More Maillard reactions in beer • Decoction - more melanoidins • Boil • High pH separate boil - wort pH is 5.0-5.4 • Longer boil (some) • Malts: • Munich, Vienna, Melanoidin • Aromatic, CaraMunich, Lighter Crystal Make your own Candi Sugar More Caramelisation • Longer boil • Strong flame • Hot Contact area • Separate smaller boil • Malts • Darker Crystal or Roasted malts
15. What is Candi Sugar? Candi Sugar • Specifically made for beer, tends to be standardised (and boring!) • Used in most Belgian style ales • Recipe kept secret by Belgian producers • Adds aroma, flavour and thins the body • Darker versions add significant flavour, especially Quadrupels • Westvleteren 12 is mostly Pilsen malt and Candi sugar • Available in rocks or syrup • Usually light, amber and dark Common misconceptions • The same as Inverted sugar • Purely to add alcohol and thin the body • Tastes like table sugar, so it’s the same Process • Conversion, Maillard reactions and caramelisation • Fairly easy to make at home
16. Equipment and safety Equipment • Large pot with high sides • Sugar thermometer • Long Spoon • Pastry brush • Eye protection • Long sleeve shirt (gloves) Extra • Ph metre WARNING: Splashing hot sugar!!!
17. Making Inverted sugar Ingredients • 1kg table sugar (sucrose) • 300-400ml of water • Acid (e.g. Lactic/Citric) – not essential Process • Heat and dissolve fully first at < 100 ͦC (10 min) • Hold between 100 and 110 ͦC (10-40 min) • Stir, Brush off crystals on the side • 1-2 tablespoon of cold water when too hot • Leave if temperature stable at a smaller flame • Should not have any browning Rocks vs. Syrup • Cool by adding water – Leave to cool • Add more water for syrup • More viscous as it cools • Result is Glucose, Fructose, Sucrose • Makes 1kg of Inverted sugar Use • Store in fridge • Syrup will thicken • Keeps for 6 months • Syrup easier to add to boil – no scorching • Heat and cool again to sanitise
18. Making Candi Sugar Ingredients • 1kg table sugar (sucrose) • Mix some with Golden syrup • 300-400ml of water • Alkaline (e.g. ½-1 teaspoon pickling lime) • Amino Acids (1 tblspn DME/Yeast nutrient) Process • Invert sugars as before (10-40 minutes) • Raise to 130 ͦC • Add Amino acids and alkaline (pH around 12) • Keep at 125-145 ͦC for 10 min - 2 hours • Stir continuously, cool by adding water • Becomes darker with time Add caramelisation • Raise and hold at 150-170 ͦC • Happens fast! (5 min) with lots of browning • Stir continuously avoid scorching Danger! • Do not leave unattended • Splatters hot sugar • Tends to boil over –> reduce heat fast! • Keep cold water at hand • Use long sleeves and eye protection
19. Making Candi Sugar After 5 min After 15 min After adding DME 60 min at 135 ͦC
20. Making Candi Sugar - Variations Variations - Alkaline (handle with care): - Pickling lime Ca(OH)2 , Lye NaOH - Baking soda NaHCO3 , Chalk CaCO3 - Amino acid: - DME, Yeast Nutrient, wort Time Lime Lime + Nutrient Baking Soda Malic Acid Acid + Nutrient Chalk Treacle+Nutrient+ Lime 5 Very sweet, no other flavor Sweet, but as much as Lime, tastes just like frosted flakes (melanoidins!) Less sweet, than Lime nutrient, otherwise tastes like sugar slightly tangy, otherwise tastes just like sugar Sweet but less so than acid, not as tangy either, slightly fruity Sweet, tastes like sugar Sweet, caramelly, some hints of frosted flakes 40 Sweet, slightly minerally and slightly chalky Toffee and dark fruits, hints of burnt sugar (not acrid or bitter) Sweet, slightly minerally- medicinal finish Strong burnt sugar flavor, slightly bitter and acrid Burnt sugar, bitter and slightly acrid Sweet, no other flavor Fruity, strong dark caramel flavor, has a hint of tanginess in the finish - Different sugars e.g. unrefined, wort - Temperatures - Length of boil - Length of Inversion - Varying quantities *Source: Ryanbrews Blog
21. Candi Sugar and beer styles Inverted sugar • Thins the body • Blonde/Golden, Tripel, Saison, Cream ale etc. Maillard reactions • Dried fruit malt, Nutty, Bread, Toasty • Dubbel, Quadrupel, Scottish ale (not “allowed” for German styles…) etc. Caramelisation • Toffee, Caramel, Nutty, Rum • Old Ale, Barley wine, Wee Heavy, Stouts etc.
22. Questions?