Starch-containing grains or cereal (cereal grains come explicitly from grass) like barley, rice, corn, wheat, and rye can be fermented into beer, whiskey, sake, or shochu. While there may be common ingredients, there are many different flavors. This difference in taste, like many other alcoholic beverages, is derived from the following:  
  • Directly from the raw materials.  For example, when malting barley, drying the barley to stop germination produces Maillard and caramelization reactions in the grain. Also, the process of boiling a mash, like in the brewing of beer, results in caramelization and Maillard reactions.
  • Through yeast metabolism during ethanol fermentation and by converting amino acids via the Ehrlich pathway into higher alcohols and carboxylic acids.
  • By esterification, which is the reaction between carboxylic acids and higher alcohols.
  • Aging due to oxidative reactions.

This article references the brewing textbook which we highly recommend reading:
[1] Kunze, W. (2004). Technology Brewing and Malting (S. Pratt, Trans.). VLB. 

Suggested Pre-reading
A Guide to Alcoholic Fermentation: www.hawaiibevguide.com/alcoholic-fermentation ​

Primary Sugar: Starch

Starch is a plant's energy source during germination and is stored within the endosperm of grain as tiny granules called amyloplasts. To create an alcoholic beverage out of starch-containing grains, the first step is saccharification, which breaks down the polysaccharide starch into fermentable monosaccharides (sugars) of glucose and fructose. In this multi-step process:
  • Enzymes that degrade starch into fermentable sugars are produced.  Different cultures have devised different methodologies for creating the enzymes, with Asian cultures utilizing exogenous microbial production like koji mold (Aspergillus spp.) and European cultures using an endogenous sprouting technique called malting.
  • Starch has a crystalline-like structure when stored in the grain’s amyloplasts. To expedite saccharification, applying heat and water breaks this structure and enables enzymes to degrade the starch into fermentable sugars. 
  • The starch and other components of the grain are degraded by the enzymes produced. This results in fermentable sugars and other degradation products. 

Starch Subunits
Starch granules are not singular molecules but rather a combination of two types of polysaccharides. 

Amylose
  • Composed of 100-400 a-glucose with a generally linear skeleton with some oxygen bridges at the 1,4-positions.
  • Percentage of starch: 20 - 25%
  • Solubility: Hot water soluble, no paste formation

Amylopectin
  • Composed of up to 6000 glucose units linked at their 1,4-positions by oxygen bridges. There are also 1,6- linkages spaced 15 to 30 glucose units apart, giving amylopectin a branched skeleton and high molecular weight.  
  • Percentage of starch: 75 - 80%
  • Solubility: Insoluble in water and forms a paste at high temperatures.

Influence of amylose and amylopectin on fermentation
Grains with high amylose content are more accessible to break down as measured by their higher utilization ratio (ratio of fermented vs. unfermented grain) [2] [3].  They also experience less starch retrogradation, which is when the amylose and amylopectin chains of cooked, gelatinized starch realign themselves when cooled, thereby reducing the degree of digestibility [4]. While this is less of an issue in brewing beer because of the high water content used for mashing, retrogradation during koji making increases the amount of sake cake (the solid by-product of sake production), and the sugar concentration in sake mash decreases. 

For more on the formation of starch
Pfister, B., & Zeeman, S. C. (2016). Formation of starch in plant cells. Cellular and Molecular Life Sciences, 73, 2781-2807. 
https://link.springer.com/article/10.1007/s00018-016-2250-x 

Matsushima, R., Hisano, H. Imaging Amyloplasts in the Developing Endosperm of Barley and Rice. Sci Rep 9, 3745 (2019). 
https://doi.org/10.1038/s41598-019-40424-w
​

Enzymes and Enzyme Development

Given the long chains of glucose that compose amylose and amylopectin, multiple enzymes are used in hydrolysis. Additionally, other enzymes are used for yeast development and the improvement of the beverage. 

Enzyme development process
The primary strategies for developing enzymes for the saccharification of starch are generally regional.
  • Malting starts with the hydration of the grain.  This initializes germination and results in the development of enzymes, including amylases. The maltster (the person doing the malting) stops the process before any starch degradation by using hot air produced by a kiln, roasting “oven,” or fire with smoke.  Malting is traditionally used in European countries.
  • Microbial enzyme production using fungi like koji (Aspergillus species) is used in Asian countries like Japan for sake and sochu, Korea for soju, and China for baiju.

Amylase enzymes
Varying glucose chain lengths result in varying final degradation products. These include the sugars maltose, glucose, and maltotriose.

α-amylase  
Role: Primarily breaks open the amylose and amylopectin chains to form dextrins of 7-12 glucose units. With each splitting, the a-amylase creates two final chains, which B-amylase can further break down. 
  • Optimal temperature: 72-75°C 
  • Denaturation temperature: >80°C. 
  • Optimal pH: 5.6-5.8
  • Commercial examples: Derived from Bacillus licheniformis and Bacillus subtilis or the fungus Aspergillus sp. [5].

β-amylase
Primarily hydrolyzes the (1→4)-α-D-glucosidic linkages of dextrins and other polysaccharides to form maltose units [6]. Minor amounts of glucose and maltotriose may also be created.
  • Optimal temperature: 60-65°C.  As β-amylase activity significantly influences the final concentration of maltose, the primary fermentable sugar in a starch fermentation, mashing is often performed at 60–65°C (140°F–149°F) [7]. 
  • Denaturing temperature:  >70°C. 
  • Optimal pH: 5.4 to 5.5.
  • Commercial examples can be derived from Trichoderma longibrachiatum
    BSG/Kerry Bioglucanase GB: bsgcraftbrewing.com/bioglucanase-gb-4-kg/

Limit dextrinase
Primarily hydrolyzes the a-(1-6) glucosidic linkages of amylopectin to form smaller linear oligosaccharide chains that subsequently are rapidly hydrolyzed by a-amylase and B-amylase. For more insight into its practical usage: https://www.creative-enzymes.com/similar/pullulanase_621.html 
α-glucosidase (EC 3.2.1.20) [Fox 2009]
Primarily hydrolyzes the release of single glucose from maltose and higher sugars. 
  • Optimal pH
    During mashing pH conditions, a-glucosidase activity is limited, and the extent of its role in malting and mashing has not been elucidated.
    • Optimal maltose pH: 4.5-4.6 
    • Optimal starch pH: 5.0. 
  • Optimal temperature: Considerably lower than the activity of other starch-degrading enzymes.
  • Commercial example Hitempase®: https://bsgcraftbrewing.com/wp-content/uploads/2021/11/Kerry-Hitempase-2XL-25Kg-Product-Data-Sheet.pdf 

Glucoamylase [9]
Lallemand’s technical sheet on its “Glucoamylase 400” product notes:
Primarily hydrolyzes both the α-1,6 and α-1,4 glucosidic linkages of starch, liberating single glucose units. This maximizes the conversion of starch, minimizes residual carbohydrates, and provides a high degree of attenuation. 
  • Optimal pH: 3.5-5.0 
  • Optimal temperature: 68-158°F. (20-70°C). 
  • Inactivation at 203°F (95°C) for 10 minutes or 212 °F at 100°C for 3 minutes.

Cellulase 
Cellulase is a complex of three enzymes: endoglucanases (EC 3.2.1.4), exoglucanases (cellobiohydrolases EC 3.2.1.91), and β-glucosidases (EC 3.2.1.21).  It primarily hydrolyze cellulose into oligosaccharides. For this reason, the beer brewing industry may add cellulase to assist with wort drainage, beer filterability, gel formation prevention, and to improve malt extraction. 
Amyloglucosidase [12]
Hydrolyzes α-1,4 and α-1,6 glycosidic bonds in starch, dextrins, and maltose from the non-reducing end until they reach a 1-6 branch point from which they cannot proceed any further. In beer brewing, it is added during the mash conversion (Saccharification) phase.
  • pH (For BSG Amylo-300): 5.4 - 5.6
  • Temperature (For BSG Amylo-300) : 55-62 °C ~(131-144 °F)  and active up to 65 °C (149 °F). 
  • Commercial example
    BSG Amylo-300: https://bsgcraftbrewing.com/wp-content/uploads/2021/11/Amylo-300-information.pdf 

Proteases and peptidases
     Made up of a diverse group of enzymes which are numerous to the extent that the category and the general end products are mentioned rather than specific enzymes.  
     Protease hydrolyzes proteins into peptides and peptidase hydrolyzes peptides into yeast assimilable nitrogen (YAN), also known as Free Assimable Nitrogen (FAN). YAN/FAN is necessary for yeast growth, as amino acids are the building blocks of proteins.  The different lengths of peptides, which are constituted by amino acid chains include:
  • Ogliopepties, which are chains of 2 to 20 amino acids [13].
  • Peptides, which are a single linear chain of amino acids. 
  • Amino acids.  Amino acids are composed of an amino group consisting of H2N (2 hydrogen and 2 Nirogen atom) hence the N in YAN/FAN. 
  • Commercial examples are derived from bacteria, Aspergillus sp. or pineapple latex and include:
    • Creative Enzymes Neutral Protease derived from Bacillus subtilis
    • creative-enzymes.com/product/neutral-protease-for-beer-brewing-food-grade-_3168.html 
    • More specifics will be covered in future articles about the saccharification of rice and the saccharification of grain. 

Common exogenously added brewing enzymes which may also be produced by koji
Exogenous enzymes may be added to address the variations in batches of ingredients like if malt has a low FAN content or address potential filtration issues.

α-acetolactate-decarboxylase (ALDC) [14]
Converts α-acetolactate to acetonin directly. This decreases fermentation time and effectively bypasses the production of diacetyl production during fermentation.
Pectic enzymes 
Prevent the formation of hazes and methanol by degrading fruit pectins.  It also minimizes the haziness caused by pectins in beer.  Examples include: BSG Pectic Enzyme Powder: https://bsghandcraft.com/pectic-enzyme-powder-1oz 

Amyloglucosidase
Hydrolyzes the ends of starch to form glucose. It may be added to beer to create lower calorie and lower carb beers, but providing glucose before other fermentable sugars can stall fermentation since the yeast will focus on it, not the other fermantables. This is known as glucose suppression/repression.
  • Optimal pH: 
    • 3.5-5.5 for White Labs Ultra-Ferm
    • 4.0-5.6 for BSG/ Kerry Amylo 3000 
  • Optimal Temperature: 
    • Below 140°F (60°C) with decomposition at 85˚C for 10 minutes for White Labs Ultra-Ferm
    • 55-62 ˚C (131-144 ˚F) and active up to active up to 65 ˚C (149 ˚F) for BSG/ Kerry Amylo 3000
  • Commercial examples can be derived from Aspergillus niger include
    • White Labs Ultra-Ferm: whitelabs.com/enzymes-nutrients-detail?id=9&type=ENZYMENUTRIENT 
    • BSG/ Kerry Amylo 3000: bsgcraftbrewing.com/amylo-300-1-kg/ 

Enzymes which improve extraction and filterability 
  • β-glucanase: From bacteria Trichoderma sp. and Orpinomyces sp.
  • Xylanase/Pentosanase: Hydrolyse pentosans of malt, barley wheat further improving extraction. It can also be helpful later in filtration.
  • Alpha-acetolactate decarboxylase: From bacteria Bacillus subtilis recombinant.

Commercial suppliers of brewing enzymes

Mechanisms of Mashing

     Heat is used to degrade the structure of the grain.  The challenge is that while higher temperatures degrade the grain structure better while retaining the enzyme activity. Optimizing maltose production during mashing is dependent primarily on temperature, with a range of 60°C–65°C (140°F–149°F) most suitable for beta amylase activity. 

Gelatinization 
The addition of hot water’s addition to the grain causes the starch molecules to swell in volume and then burst. By breaking starch’s crystalline structure and forming a gelatinous solution, amylase enzymes can better interact with the starch. Cereals vary in gelatinization temperature, and those with higher gelatinization temperatures require longer cooking  [16] rather than higher temperatures as amylase enzymes rapidly denatured above 160 °F (71 °C) [17].  Special methods like decoction mashes can also be used. 

Factors that influence gelatinization
Marconi et al. (2017) noted these factors include: the gel water content, amylose content, degree of crystallinity in the amylopectin fraction, amylopectin chain length, and the placement and content of starch granule-associated protein and lipids. 

Gelatinization temperatures of different grains
  • Malt and barley starch gelatinizes at 60°C (140°F)
  • Corn starch gelatinizes at 62–80°C is equal to 143.6°F.
  • Rice starch gelatinized at 80 to 85°C (175 -185°F) 

Liquefaction 
The reduction of the gelatinized starch’s viscosity by α-amylase is known as liquefaction.  The addition of hot water increases the rate of contact between α-amylases and starch’s amylose and amylopectin by dispersing and increasing the kinetic energy of the starch molecules. 

Measurements of Saccharification

Diastatic power 
The combined starch-converting ability of the enzymes a-amylase, B-amylase, α-glucosidase, and limit dextrinase into fermentable sugars is called diastatic power. It is often provided on a malt spec sheet in degrees Lintner (per pound of grain) in the United States.  The concept is the same in sake production, although it is not specifically measured.  Additional insight into diastatic power will be discussed in a future article about the malting of barley. 

Attenuation [18]
The percentage of sugars converted into ethanol and CO2 is measured by apparent attenuation (AA).  This relative percentage is calculated by comparing the hydrometer readings of a beverage’s final gravity (FG) to the original gravity (OG) using the equation AA=(OG-FG)/ (OG-1).

Influence on flavor
A higher percentage of attenuation results in a drier and more alcoholic beverage than a less attenuated beverage made from the same wort because more sugar is converted.
​
Influenced by yeast strain
Some yeast strains have higher levels of attenuation due to a higher production of enzymes capable of converting polysaccharides into fermentable sugars. Major yeast suppliers provide attenuation ranges as part of their product information. 

Other factors influencing attenuation
  • The water-to-grist ratio and the mash pH, as thinner mashes have higher degrees of attenuation.
  • Higher temperatures accelerate attenuation; however, unwanted flavors may also be produced. Raising the temperature near the end of fermentation can be used to offset this issue.
  • Yeast pitching rate increases correspond to increases in the speed of fermentation; however, overpitching can reduce yeast growth and lead to yeasty-tasting beer. Sluggish yeast growth can be mitigated by oxygenation and nutrient addition.
  • Yeast agitation can improve attenuation. 
​

Enzymatic Degradation Products

Starch degradation into sugars

Dextrins 
These oligosaccharides come in both branched and unbranched form factors due to the different structures of amylose and amylopectin. Limit dextrins are a specific type that is linear in structure. 
  • Formation occurs when α-amylase breaks down linear and branched dextrins of varying lengths randomly along its carbon chain.  Limit dextrins are formed when Beta-amylase cleaves off the maltose units from the non-reducing end of the starch chain.
  • Fermenablility: Dextrins require further breakdown to be fermentable by Saccharomyces cerevisiae into ethanol.  However, dextrins can enhance the texture of beer by adding “body” [20].  To achieve this, some beer recipes intentionally increase the amount of dextrins by prolonging the mash at a higher temperature range or using high-dextrin malts like caramel or crystal malts [21]. 
​Maltose 
This disaccharide is composed of two glucose molecules linked together. 
Formation occurs when Amylase enzymes cleave starch molecules primarily at the α-1,4 glycosidic bonds, releasing maltose units. 
  • Fermentability: Maltos is fermentable by Saccharomyces cerevisiae, but only after glucose is exhausted. This occurs as glucose represses the synthesis of maltose transporters, maltotriose transporters, and the α-glucosidases (maltases) that hydrolyze these sugars inside the cell. 
  • Percentage in beer brewing: 65%

Maltotriose: 17.5%
This trisaccharide has a branched chain structure and is made up of three glucose units linked by α-1,4 glycosidic bonds.
  • Formation occurs when amylopectin is degraded, and forms a branched structure due to amylopectin’s branching.
  • Fermentability: Though S. cerevisiae strains generally ferment maltotriose, but only after glucose and maltose exhaustion, some strains do not ferment it at all. If fermentation does occur, the branched-chain structure of maltose is hydrolyzed by α-glucosidases at branches formed by the α-1,6 glycosidic bonds. Given maltotriose’s complex structure, this process is slower than the breakdown of maltose.

Glucose
It is the primary fermentable sugar by Saccharomyces cerevisiae, though not a significant end product during mashing.  
It is sometimes formed when amylase enzymes, especially α-amylase, further break down dextrins into individual glucose molecules.

β-glucan
     Hemicellulose, the primary constituent of the endosperm’s wall, is comprised of 80-90% β-glucan, with levels varying by grain, cultivar, and grain processing method . During gelatinization, β-glucan is released when the starch granule’s structure is disrupted. These β-glucans are composed of long chains of glucose molecules bound together by 1,3-, and more often, 1,4-bonds are structurally fringed micelles (they look like a fringed carpet).  These fringes allow the micelles to hydrogen bond with each other, especially in the presence of proteins, to form a gel.  Problematically, this gel reduces extract yields, increases wort and beer viscosities, contributes to haze formation, reduces filterability, and causes issues with machine operations like pumps. Additionally, its problems do not come with benefits like improvements in the texture or aroma; therefore, formation should be avoided.

β-glucan gel formation is influenced by

Alcohol concentration because this prevents B-glucan gel formation.  Problematically, the gel can form after packaging. 

Shear forces are forces that act parallel to a surface, causing different layers of the surface to move relative to each other, and can be thought of as the forces that cut or slice through an object. These forces occur during pumping or swirling motions and result in β-glucan’s hydrogen bonds reforming by crosslinking due to the molecule being stretched out (Kunze).  These forces and the corresponding hydrogen bonding can be mitigated by:
  • Slow depressurization after cooking 
  • Slow cooling of the wort
  • Calm sedimentation without swirling
  • Stirring slowly while not under stirring because under-stirring would cause separation of the grain and water and create temperature gradients. Beer brewing stirring techniques include slowly rotating (<1 m/s) large agitator blades that adapt to changes in viscosity. 
  • Minimizing pressure differentials that can come from pumps, agitator blades, centrifuges, pipes with sharp bends, rough internal surfaces of pipes on through which fluid flows, and narrow gaps of positive-displacement pumps, pipes, and vessels in which turbulence occurs.

Temperature
  • Temperature influences on viscosity. 
    • At 30-35°C the viscosity is initially high
    • At 50 to 52°C it is considerably lower and increases significantly at >60°C due to the commencement of gelatinization. In the case of rice mashes, viscosity increases later because of a higher gelatinization temperature and reaches a maximum of 80°C or higher. 
  • Optimal temperatures for glucanase enzymes (Kunze)
    • Endo-β-1,4, glucanase: 45 to 50°C
    • Endo-β-1,3, glucanase: 60°C
    • β-glucan-solubilase 62°C
    • Solubilization by the breaking of hydrogen bonds: During wort boiling at above 70-80°C 
    • Condensation: During wort cooling at ~20°C and gives rise to activated B-glucan which on cooling.

Malting process and grain selection
This is where β-Glucans are primarily degraded [1]. A friabilimeter value of 85% can be used to distinguish grains with low B-glucan content. 

Endo-β-glucanase degrades the β-glucan portion of the interlinked micelles. 
This degradation is enhanced in beer brewing by resting the mash at 45 to 50°C for an extended period and using a well-modified malt with a high endo-β-glucanase content.

Commercial example of β-Glucanase
White Labs Visco-buster  (endo-beta-1,3-1,4-glucanase)
www.whitelabs.com/enzymes-nutrients-detail?id=11&type=ENZYMENUTRIENT 


Protein Degradation 
Many high molecular weight proteins and protein derivatives precipitate out during mashing.  Important protein degradation products include:

High molecular weight degradation products (for beer)
Thees can enhance mouthfeel as is the case with hazy IPAs and foam stability.  In particular foam enhancement is influenced by the release of hordein and glutelin protiens at >60°C.  Excessive levels can create undesirable hazes or result inan undesirable, watered-down brew [5].

Low molecular weight degradation products,
Prolin in particular constitutes part of  FAN/YAN.  This release occurs at 45-50°C, especially forming peptides and amino acids.

Degradation is influenced by

Temperature
Optimum temperatures proteolytic enzymes temperatures: 
  • Endopeptidase: 45-50°C (113-122 °F)
  • Carboxypeptidase 50°C (122 °F)
  • Aminopeptidase 45°C (113 °F)
  • Dipeptidase 45°C (113 °F)

Extent of malt-modification
Well-modified malt supplies a sufficient quantity of α-amino acids.  However, directly adding glucose or sucrose adjuncts to the wort can require additional amino acids for complete fermentation. These amino acids can be directly added or an amino acid rest at 45-50°C can be used to allow for protease and peptidase to create additional FAN/YAN.

Lipid Degradation
Lipids from the grain are typically in the form of unsaturated fatty acids. These lipids are necessary for yeast development as they are components of the yeast cell membrane.  Since sake polishing removes most of the rice’s lipids, these have different functions and will be discussed separately in an issue specifically about rice saccharification and an issue about the brewing of beer. 

Insoluble substances
Starch, cellulose, some high molecular weight proteins, gums, tannins, mineral matter, and other compounds will folloculate out (drop out of solution) at the end of the mashing process [1]. The removal of these solids varies by what is being produced. For example, solids are removed before fermentation in beer, whereas grains are removed after fermentation in sake, and fermenting with grains varies in whiskey production. The variation of these removal times is related to the desired extraction of compounds from the residual solids. 

Process Step
Sake
Beer
Distilling
Main 
Ingredients
Rice, Koji
Malted Barley
Various Grains
​Mashing
Rice & Koji mixed with water & yeast
Malted barley mixed with water & yeast
​Grains mixed with water & yeast
Fermentation
Multiple parallel fermentations with yeast strains
Single anaerobic fermentation with yeast
​Single anaerobic fermentation with yeast
Lautering
Not used
Separation of liquid wort from grain solids
Sometimes grain is strained off before distillation

Sources and Suggested Reading

  1. www Kunze, W. (2004). Technology Brewing and Malting (S. Pratt, Trans.). VLB.
  2. Aramaki   I, Yoshii   M, Iwase   S, et al. Correlation between structural properties of amylopectins and the sake brewing or physicochemical properties of rice. J Brew Soc Jpn. 2004;99: 457–466. in Japanese. jstage.jst.go.jp/article/jbrewsocjapan1988/99/6/99_6_457/_pdf/-char/en
  3. Okuda   M, Aramaki   I, Koseki   T, et al. Structural characteristics, properties, and in vitro digestibility. Cereal Chem. 2005;82: 361–368.  https://doi.org/10.1094/CC-82-0361  
  4. Wikipedia contributors. (2023, May 1). Retrogradation (starch). In Wikipedia, The Free Encyclopedia. Retrieved 10:25, May 29, 2023, from https://en.wikipedia.org/w/index.php?title=Retrogradation_(starch)&oldid=1152630775
  5. Wang, E. (2022). There’s an Enzyme for That. Five Star Chemicals. Retrieved December 21, 2023, from www.fivestarchemicals.com/blog/theres-an-enzyme-for-that/  
  6. Wikipedia contributors. (2022, November 29). Beta-amylase. In Wikipedia, The Free Encyclopedia. Retrieved 04:11, February 9, 2023, from https://en.wikipedia.org/w/index.php?title=Beta-amylase&oldid=1124506263
  7. Philliskirk, G. (n.d.). Wort. Beer and Brewing Magazine. Retrieved December 29, 2023, from https://beerandbrewing.com/dictionary/700VNHCdWa/ 
  8. Fox, G. P. (2009). Chemical composition in barley grains and malt quality. In Genetics and improvement of barley malt quality (pp. 63-98). Berlin, Heidelberg: Springer Berlin Heidelberg.  Retrieved from: https://pages.uoregon.edu/chendon/coffee_literature/2009%20Genetics%20and%20Improvement%20of%20Barlet%20Malt%20Quality,%20Chemistry%20of%20Malt.pdf
  9.  Lallemand Brewing. (n.d.). ABV Glucoamylase 400. Lallemand Brewing. Retrieved December 2, 2023, from www.lallemandbrewing.com/docs/products/tds/TDS_ABV_ENZYMES_GLUCOAMYLASE-400_ENG_DIGITAL.pdf  
  10. Chakraborty, S., Gupta, R., Jain, K. K., Gautam, S., & Kuhad, R. C. (2016). Cellulases: Application in Wine and Brewery Industry. New and Future Developments in Microbial Biotechnology and Bioengineering, 193-200. Retrieved from: www.researchgate.net/publication/306081707_Cellulases_Application_in_Wine_and_Brewery_Industry 
  11. Islam, M., Sarkar, P. K., Mohiuddin, A. K. M., & Suzauddula, M. (2019). Optimization of fermentation condition for cellulase enzyme production from Bacillus sp. Malaysian Journal of Halal Research, 2(2), 19-24.  https://intapi.sciendo.com/pdf/10.2478/mjhr-2019-0009 
  12. BSG Craft Brewing. (2021). Amylo 300. Retrieved December 9, 2023, from
    www.bsgcraftbrewing.com/wp-content/uploads/2021/11/Amylo-300-information.pdf
  13. Wikipedia contributors. (2023, October 23). Oligopeptide. In Wikipedia, The Free Encyclopedia. Retrieved 08:32, December 6, 2023, from https://en.wikipedia.org/w/index.php?title=Oligopeptide&oldid=1181429025
  14.  BSG Craft Brewing. (n.d.). ALDC - 1 kg. Retrieved December 9, 2023, from https://bsgcraftbrewing.com/aldc-1-kg/
  15.  Li, Z., Liu, W., Gu, Z., Li, C., Hong, Y., & Cheng, L. (2015). The effect of starch concentration on the gelatinization and liquefaction of corn starch. Food Hydrocolloids, 48, 189-196.  https://linkinghub.elsevier.com/retrieve/pii/S0268005X15001022  
  16. Marconi, O., Sileoni, V., Ceccaroni, D., & Perretti, G. (2017). The use of rice in brewing. Adv. Int. Rice Res, 49-66.  www.intechopen.com/chapters/53124 
  17. Cadenas, R.; Caballero, I.; Nimubona, D.; Blanco, C.A. Brewing with Starchy Adjuncts: Its Influence on the Sensory and Nutritional Properties of Beer. Foods 2021, 10, 1726. https://doi.org/10.3390/foods10081726
  18. Carpenter, D. (2017, January 3). Everything You Need to Know About Attenuation. Beer and Brewing Magazine. Retrieved December 29, 2023, from www.beerandbrewing.com/everything-you-need-to-know-about-attenuation/  
  19. Enzyme Innovation. (2018, August 5). Flocculation and Attenuation Explained. Retrieved December 2, 2023, from www.enzymeinnovation.com/flocculation-attenuation-explained/
  20. Craft Beer & Brewing. (n.d.). Dextrins. Craft Beer & Brewing. Retrieved December 2, 2023, from www.beerandbrewing.com/dictionary/7ymtLJGtZT/ 
  21.  BYO. (2023, December 19). Brew a Great Non-Alcoholic Beer. Retrieved December 9, 2023, from www.byo.com/article/brew-a-great-non-alcoholic-beer/
  22. Vidgren, V., Ruohonen, L., & Londesborough, J. (2005). Characterization and functional analysis of the MAL and MPH Loci for maltose utilization in some ale and lager yeast strains. Applied and environmental microbiology, 71(12), 7846–7857. https://doi.org/10.1128/AEM.71.12.7846-7857.2005
  23. Alves-Jr, S. L., Herberts, R. A., Hollatz, C., Miletti, L. C., & Stambuk, B. U. (2007). Maltose and maltotriose active transport and fermentation by Saccharomyces Cerevisiaes. Journal of the American Society of Brewing Chemists, 65(2), 99-104. Retrieved from:  academia.edu/29670520/Molecular_Analysis_of_Maltotriose_Active_Transport_and_Fermentation_by_Saccharomyces_cerevisiae_Reveals_a_Determinant_Role_for_the_AGT1_Permease
  24. Heisel, S. E. (2006). Chapter 2: Providing cereals for brewing. In C. W. Bamforth (Ed.), Brewing: New Technologies (pp. [pp. 10-29]). Woodhead Publishing. Retrieved from: academia.edu/34914369/Bamforth_Brewing_New_Tehnologies
  25. Preiss. R., (2021). Dude, Where’s My Haze? Advice for Hazy IPAs. Escarpment Labs. Retrieved December 19, 2023, from www.escarpmentlabs.com/en-us/blogs/resources/dude-wheres-my-haze-advice-for-hazy-ipas