General Overview : Mash Side Details

By: Jason McCammon

With: Mike Smith

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, Mashing…

This To that.

What are Enzymes?

Active protein molecules (non-living)

Created by almost every living thing.

Present in saliva, stomach, etc.

Also called Koji Fermentation Semi-Solid Maintain 50% H2O

Enzyme Production

Submerged Fermentation

Solid State Fermentation

Very similar to a distiller’s fermentation.

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.

Enzyme Properties

What do they look like?

3-D Structure

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.

How Can Enzymes Help?

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.

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

Infusion Mashing

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

Gelatinization table

Various Grains Temp range (oC) Temp Range (oF)

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

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

Gelatinization

Starch is present in two major forms.

Amylose – straight chains of glucose

Amylopectin – branched chains of glucose

The branched chains (α-1,6 bonds) cannot be broken by “regular” enzymes.

Starch Properties

v

Alpha – 1,6 bond

Alpha – 1,4 bond

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

Liquefaction

Alpha-amylase

Beta-amylase

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

Liquefaction

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

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?

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.

Starch isn’t Everything

Alternative Sugars

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.

Fruit 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

Sugar Mashes

Various Starch/Sugar Sources...

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

Local Grain Sourcing

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.

Recap

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 - 1

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 - 2

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 - 3

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?

Troubleshooting - 4

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 yield

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 #

Calculating Conversion

Theoretical Calcs

Any Questions? Or should we get Distilling?

Finish