General Overview : Mash Side Details
By: Jason McCammon With: Mike Smith Mashing
Typically a combination of milled grain and water where the mash is heated.
Common mashing steps include: Gelatinization Liquefaction Saccharification Or SSF (Simultaneous Saccharification and Fermentation)
Breaking down starch is most commonly accomplished with enzymes.
Mashing, Mashing…
This To that. What are Enzymes?
Active protein molecules (non- living)
Created by almost every living thing. Present in saliva, stomach, etc. Enzyme Production
Submerged Fermentation
Very similar to a distiller’s fermentation.
Solid State Fermentation Also called Koji Fermentation
Semi-Solid
Maintain 50% H2O Enzyme Properties
Enzymes are proteins that act as Catalysts.
As such they do not get used up in the reaction.
Important factors are: pH, temperature, and substrate concentration. What do they look like?
3-D Structure How Can Enzymes Help?
Conversion of starch to sugar. No sugar = no fermentation = no alcohol
Other enzymes can be of assistance depending on the situation at hand. Cellulase, Protease, Beta-Glucanase, Pectinase, etc.
Common sources of enzymes are malted grain, or commercially purchased enzyme. Infusion Mashing
Typical style used for beer or scotch style whisky Malted barley (or malted grain) is majority of grain bill. Malt has its own enzymes to convert starch. Infusion Mashing
This is a “two in one” process, as malt has both beta-amylase and alpha-amylase available to convert starch into sugars.
Easier method to get good results.
Infusion Mashing
When using malt as a minority to convert the whole mash, be mindful of the DP (Diastatic Power) of the malt.
Malt is an exception, not the rule.
As distillers, it is in your best interests to know more about starch conversion
Gelatinization
The process of extracting the starch in grain into water, allowing us to begin the breakdown process of starch into sugar. The more finely ground the grain is, the easier the gelatinization will be. Must happen in the presence of water and heat to encourage water uptake Gelatinization table
o o Various Grains Temp range ( C) Temp Range ( F) Wheat 58-65 135-149 Barley 52-60 125-140 Rye 55-70 131-158 Rice 68-78 154-172 Sorghum 68-78 154-172 Oats 58-72 135-162
Corn (generic yellow) 65-75 149-167
Millet 56-70 132-158 Gelatinization
Different grains have different common gelatinization temperature ranges.
If the grain was pre-modified, it will be easier to hydrolyze the starch i.e. Malt, Rolled grain, Flaked grain, etc.
Higher temps will increase rate of gelatinization Starch Properties
Starch is present in two Alpha – 1,4 bond major forms. Amylose – straight chains of glucose Amylopectin – Alpha – 1,6 bond branched chains of glucose v The branched chains (α- 1,6 bonds) cannot be broken by “regular” enzymes.
Liquefaction
The stage where the gelatinized starch is broken down by an alpha-amylase (typically) into dextrins. Dextrins = random sugars (small chain to long chain)
Alpha-amylase – endo (interior) amylase that cuts interior α-1,4 glycosidic (glucose-glucose) bonds randomly.
Liquefaction
Alpha- amylase
Beta- amylase Liquefaction
The pH plays a large role in optimal liquefaction. Adjust as necessary for best enzyme activity.
There are three different kinds of alpha- amylase available to distillers currently. Low temp (80 – 135 F). pH = 4.0 – 6.0 Med temp (120 – 165 F). pH = 4.5 – 7.5 High temp (175 – 190 F). pH = 5.6 – 6.5
Saccharification
This step comes after liquefaction, it is the further breakdown of dextrins into small sugars that can be fermented by yeast. Is usually accomplished at lower temperature ranges Malted Grain Beta-amylase (130-145oF avg) Exogenous Beta-amylase (80 – 140oF avg) Primarily produces maltose sugars Glucoamylase (80 – 140oF avg) This is a different amylase. Instead of producing maltose, it will produce glucose. Has alpha -1, 6 activity to degrade amylopectin. Sugar Saccharification
Glucose Maltose (glucose-glucose) Saccharification
Necessary step to produce sugars small enough for yeast to eat.
Beta-amylase will leave residual sugars.
Glucoamylase can produce up to a 95% fermentable mash
Old Ways – Best Ways?
Starch isn’t Everything
Other sources of fermentable sugar are available and can produce excellent spirits.
There are less common starch sources like Agave or Jerusalem artichokes that store their starch as “Inulin” instead of amylose/amylopectin.
Many of the more popular spirits will be made from the regular starch sources. Due to laws and cost. Corn, wheat, barley, rye, rice, millet, sorghum, etc.
Alternative Sugars
Fruit Mashes
Most fruits have their sugars in an available form as either fructose, glucose, or sucrose. Notable exceptions are Apples and Pears
Most fruit could do with a mild pectinase treatment to enhance extraction/reduce viscosity. Exogenous pectinases work well at native pH
Some fruits require pH adjusting (acidify) to prevent spoilage and enhance fermentation.
Sugar Mashes
Anything that has to do with directly fermentable sugar. Table sugar, molasses, agave syrup, honey, etc. pH will need to be adjusted and maintained
Step nutrient and sugar additions are highly recommended Various Starch/Sugar Sources...
Local Grain Sourcing
Highly recommended for distillers as it promotes local economy, reduces costs(in some cases), etc.
Can work with local farmers to get them to grow what you want and make a spirit that abides by state sourcing laws
Local Grain Sourcing
Recommend establishing some form of testing to better predict results from each new batch of grain.
Problems can be large, so can benefits Crop variation Farm variation
Good option, but be mindful of the whole situation.
Local Grain Sourcing
Recap
With few exceptions, mashing will require these steps Gelatinization Liquefaction Saccharification
Getting the yields and profitability that you want will require measurements, excessive note taking, and the ability to troubleshoot. Troubleshooting - 1
Low Starting Gravity(Brix) Was there a pH test of the mash? Were there sufficient enzymes in the mash to convert the starch to sugar? Was the mash held for long enough for them to work? Was the starch sufficiently gelatinized at the beginning? Was there enough grain in that amount of water? Was an Iodine test for starch presence done? How was the gravity/Brix measured?
Troubleshooting - 2
High Finishing Gravity(Brix) What was the sugar source in the mash? Starch from grain, glucose, molasses, malt, etc. Was an Iodine test for starch done (if necessary)? Were possible unfermentable sugars added? Was there a “saccharification” step (if necessary)? Did the fermentation behave erratically?
Troubleshooting - 3
Low Extractions Iodine Test for Starch? Was the pH of the mash checked? Sufficient enzyme content? (Malt or exogenous) Was the grain milled efficiently? Sufficient agitation? Was the mash lautered or transferred wholesale? How hot did the mash get? And for how long? How trustworthy is the thermometer?
Troubleshooting - 4
Stuck Fermentations What is the mash material? Were yeast nutrients used? Was enough yeast pitched? Was the yeast strong enough to handle the mash/osmotic pressure? What are the cleaning methods in the distillery? How often are vessels cleaned and sanitized? What was the fermentation temperature (or range)? Open or Closed Fermentation? Calculating yield
Theoretical Sugar Yield 1668 lbs. of wheat starch at 95% starch content. Using 500 gallons of water.
1668 x .95 = 1585lbs of starch = 1585lbs of sugar (assuming no losses etc.) Impossible to achieve, but for the sake of calculations...
1585lbs sugar/4170lbs water = 38% sugar solution (roughly) or 38.34g/100mL (exactly) This would result in about a 19% abv if fully converted Calculating Conversion
Theoretical Ethanol Yield Using previous info… 1585lbs of sugar x 51.1% (Gay-Lussae Yield) = 809.9lbs of ethanol
809.9lbs of ethanol x 1gallon/6.58lbs ethanol = 123.1 gallons ethanol (200 proof)
123.1 gallons ethanol x 95% yield = 116.9 gallons ethanol (200 proof) This is the efficiency yield, obviously not a real #
Theoretical Calcs
Finish
Any Questions? Or should we get Distilling?