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Exploration of Step Mashing: What, Why and Recommendations

Exploration of Step Mashing: What, Why and Recommendations

This presentation was given at the May, 2021 meeting of the London Amateur Brewers (LAB) by Serge Savin.

London Amateur Brewers

May 10, 2021

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  1. Exploration of Step Mashing: What, Why and Recommendations S E

    R G E S A V I N , L A B , M A Y 2 0 2 1
  2. Background • Curious why Belgian breweries employ and advocate a

    step mashing process • Wanted to understand the impact of mash schedule on head retention • Conceptually against using head enhancing malts • Believed brilliant head retention can be achieved with process • Have always noticed that decocted beers have wonderful head retention • Wanted to explore the enhancement of phenolic expression via mash schedule, rather than fermentation
  3. Why bother? • Improve clarity by converting long chain proteins

    into medium and short chain proteins, especially when using wheat and rye • Reduce chill haze by breaking down gummy carbohydrates • Improve phenolic expression for styles like Wit and Weissbier • Improve head retention without special malts (Carapils, Carafoam, etc) • Add that elusive Belgian digestibility/drinkability to your beers
  4. What I will not cover (some other variables that affect

    your mash…) • Decoction (a step mashing process at it’s heart) • Turbid mash (a whole different ball game and for completely different reasons) • Impact of common temperature rests on mouthfeel/body (e.g. 66C vs 69C) • Impact of temperature rests’ length • Impact of grist-to-water ratio • Impact of pH on enzymatic activity (pH information in this presentation is not accurate!) • Impact of malt protein content and malt modification (degree of breakdown of the protein-starch matrix) • E.g. it is possible that employing a protein rest with fully modified malt (which has very little, if any, long chain proteins) could negatively affect head retention
  5. What I did • Brewed 7 batches of beer (during

    the 1st lockdown) across 3 styles, keeping everything as identical for every style (including mistakes and mishaps) as I possibly could • For consistency, all batches included a mash out step at 78C for 30 mins (to halt enzymatic activity of converting starches into sugars) • Originally the plan was to bring a ton of beer to a LAB meetup and conduct triangle tests before discussing each experiment • For obvious reasons this hasn’t happened, but some of you have recently received these beers by post to see for yourself if there is any impact from difference in process – or not!
  6. What is step mashing? • The process of conducting multiple

    mash rests across a range of temperatures, 37-78C • Can be achieved by adding hot water to hit particular temperatures • Requires a separate vessel to heat up water • Difficult to calculate the exact volume and temperature needed for an infusion • Requires careful control over mash pH • The traditional way, I’ve done this a few times and it works rather well • Can also be achieved by an electric all-in-one unit, recirculation mash system or a mash tun with an element • The easy way with very little effort needed • The reason I went electric • Each step is specifically selected to prioritise activity of a particular enzyme – or to exclude it altogether • Enzyme – a protein that acts as a biological catalyst for a specific biochemical reaction • For brewing, specific enzymes convert starches/dextrins (long chain sugars) into simpler sugars that yeast can metabolise, as well as transform long chain proteins found in malt into medium and shorter chain proteins The above diagram is not entirely correct, more on this later..
  7. Lets talk about the enzymes… …Beta-glucanase • Traditionally, an acid

    rest at 37C was used in order to lower mash pH by: • Promoting Lactobacillus growth • Letting Phytase enzyme work on phytin found in grains • Very easy to judge by sticking your finger into the mash (37C is body temperature) • However, many other bacteria are also present on the malt and aren’t that beneficial (e.g. Pediococcus) and it takes a very long time, 1-2hrs+ • There is a much more useful enzyme active in this temp range – Beta-glucanase • Active Temp – 20-50C • Preferred Temp – 40C • Beta-glucanase will degrade beta-glucans, which are a form of carbohydrates • Beta-glucans are found in highest concentrations in unmalted rye, wheat, oats and undermodified malts and can lead to chill haze • A 20-30 mins rest at 40C will break down beta-glucans, especially important if using >20% of unmalted adjuncts and clarity is required Beta-glucanase
  8. Lets talk about the enzymes… …Proteinase & Peptidase • Protein

    rest has a large temperature window, with two enzymes active that break down proteins – Proteinase and Peptidase (Proteolytic enzymes) • Some sources mention that both enzymes are active in the same temperature window (20- 65C) and some that they are most active at different temperatures • Proteinase breaks down long chain proteins into medium chain proteins • Active Temp – 50-60C • Preferred Temp – 57C • Peptidase breaks down moderate to short chain proteins into their component form • Active Temp – 45-55C • Preferred Temp – 50C • Long chain proteins can lead to haze and instability, whereas medium chain proteins are beneficial for body and head retention • At temperatures ~45C ferulic acid is released from being bound to other molecules and is a precursor to 4-vinyl-guaiacol (4VG), which we perceive to have clove-like aroma • A 15-20mins rest at 57C will maximise head retention and improve clarity and a 20-30 mins rest at 45C will maximise clove aroma with a POF+ (phenolic off flavour positive) yeast Beta-glucanase Proteinase . Peptidase
  9. Lets talk about the enzymes… …Alpha-amylase & Beta-amylase • Starch

    conversion is down by two distinct and more familiar enzymes - Alpha-amylase & Beta-amylase (Diastatic enzymes) • Alpha-amylase breaks down starches at random points, creating new – but still complex – dextrinous carbohydrates • Active Temp – 60-71C • Preferred Temp – 67-70C • Beta-amylase ‘attacks’ the ends of starch molecules, producing maltose, which is highly fermentable (starch molecules can be very long, so it takes a while for the full conversion to take place if only beta-amylase is active) • Active Temp – 55-65C • Preferred Temp – 63-65C • A long rest at optimum temperatures for beta-amylase will produce a highly fermentable wort that will result in a ‘dry’ final product, whereas a rest at optimum alpha amylase temperatures will improve body and add a rich smooth mouthfeel • Glycoprotein rest - resting mash at 70-72C for 15-30 mins results in formation of glycoproteins, which stabilise head and further aid retention Beta-glucanase Proteinase . Peptidase Beta- amylase Single rest Alpha- amylase
  10. “Escondite” – Belgian Golden Strong Single Rest vs Step Mash

    Recipe: • 85% Dingemans Pilsen • 15% Clear Candi Rock Sugar • Hersbrucker/Styrian Golding • Wyeast 1388 (Duvel) Single Rest Step Mash Mash Schedule 66.5C for 102 mins 56C for 15 mins 63C for 45 mins 70C for 30 mins Fermentation Stats 1.064 OG 1.003 FG 8.3% 1.064 OG 1.005 FG 8.0% ~3 months • Slightly loose head • Doesn’t bounce much • No lacing • Under 4 mins retention • Easily roused • Fade quickly when roused • Moussy head • More vigorous when pouring • Some lacing • 4+ mins retention • Easily roused • Stays tight/holds when roused • 1/5 correct attempts to identify by aroma/flavour in a triangle test at ~4C • Once warmed up to near room temperature, difference became more apparent, step mash beer was noticeably smoother vs harsh edgy single rest ~12 months • Aroma: M spicy, M floral, ML citrus, ML herbal phenolic • Flavour: MH herbal phenolic, L grainy • Aroma: L spicy, L floral, no citrus, H herbal phenolic • Flavour: M herbal phenolic, M grainy • Noticeably smoother and married together
  11. “Bière du Confinement” – Bière de Garde Peptidase vs Proteinase

    vs No Protein Rest Recipe: • 43.5% Crisp Hana • 25.5% Barke Munich • 11.5% Spelt • 11% Malted Rye • 3.5% Crystal 130 • 3.5% Roasted Rye • 1% Caramunich I • Magnum/Lubelski/Styrian Golding • Yeast Bay Wallonian Farmhouse Peptidase Proteinase No Protein Rest Mash Schedule 50C for 40 mins 67C for 60 mins 57C for 40 mins 67C for 60 mins 67C for 60 mins Fermenta tion Stats 1.050 OG 1.004 FG 6.1% 1.050 OG 1.004 FG 6.1% 1.050 OG 1.004 FG 6.1% ~3 months • Touch more phenolic • Stinkier/dungier • Very tight head • Moussy • Sticky • Sharper roast • Tallest when roused • Very tight head • Moussy • Stickiest • Less flavour definition • Less aromatics • Very tight head • Moussy • Sticky ~12 months • Aroma: M chocolate, MH spicy phenolic, L floral • Flavour: L chocolate, L spicy, M spicy phenolic, • Mouthfilling, smooth • Aroma: ML chocolate, M spicy phenolic • Flavour: VL chocolate, VL spicy, MH spicy phenolic, light flavour • Not as smooth • Aroma: M fishy, L chocolate, L spicy phenolic • Flavour: VL chocolate, VL spicy • Mouthfilling, somewhat harsh, unpleasant
  12. “Quick Draw McGraw” – Belgian IPA Single Rest vs Glycoprotein

    Rest Recipe: • 89% Dingemans Pilsen • 5% Barke Vienna • 3% Crystal 100 EBC • 3% Dark Brown Sugar • Jester/Hersbrucker/Mittlefruh/Citra • Wyeast 1762 (Rochefort) Single Rest Glycoprotein Rest Mash Schedule 65C for 60 mins 65C for 60 mins 72C for 30 mins Fermentation Stats 1.044 OG 1.008 FG 4.8% 1.044 OG 1.008 FG 4.8% ~12 months • Aroma: MH floral, L honey, ML spicy, VL grainy • Flavour: VL floral, VL honey, M spicy, L grainy • Aroma: H floral, L honey, MH spicy, ML grainy • Flavour: L floral, L honey, M spicy, ML grainy • Somewhat smoother
  13. My Mash Schedule Recommendations Profile/Rest Beta-glucanase Peptidase Proteinase Beta-amylase Alpha-amylase

    Glycoprotein All beers   57C for 15 mins 67C for 60 mins 72C for 30 mins Improve clarity, wheat/rye/oats 40C for 20 mins  57C for 15 mins 67C for 60 mins 72C for 30 mins Phenolic expression  45C for 20 mins 57C for 15 mins 67C for 60 mins 72C for 30 mins Belgian   57C for 15 mins 63C for 45 mins 70C for 30 mins 72C for 30 mins
  14. Conclusions • No noticeable improvements to clarity as a result

    of protein rests and the 40C beta- glucanase rest hasn’t been explored to address chill haze • While a Wit/Weissbier yeast hasn’t been used and the peptidase rest wasn’t as low as 45C, phenolic expression has been noticeably increased with a rest 50C • Profound improvement to head retention, especially from a Glycoprotein rest at ~72C • Step mashed beers were more cohesive/smoother and had that intangible element • Somewhat noticeable improvement to flavour stability • A very versatile tool in the brewing arsenal at the expense of an extra hour or so!