1
Q
What the does the term Modification mean?
A
Modification is the term that describes the degree of breakdown during malting of the protein-starch matrix (endosperm) that comprises the bulk of the seed.
2
Q
Why do moderately-modified malts benefit from a protein rest?
A
Moderately-modified malts benefit from a protein rest to break down any remnant large proteins into smaller proteins and amino acids as well as to further release the starches from the endosperm.
3
Q
Do fully-modified malts need a protein rest?
A
Fully-modified malts have already made use of these enzymes and do not benefit from more time spent in the protein rest regime. In fact, using a protein rest on fully modified malts tends to remove most of the body of a beer, leaving it thin and watery. Most base malt in use in the world today is fully modified.
4
Q
Most wort proteins, including some enzymes like the amylases, are not soluble until the mash reaches temperatures associated with the protein rest (113-131°F). What are the two main proteolytic enzymes found at this stage of the mash?
A
The two main proteolytic enzymes responsible are peptidase and protease.
5
Q
Describe the proteolytic enzyme Peptidase.
A
Peptidase works to provide the wort with amino acid nutrients that will be used by the yeast
6
Q
Describe the proteolytic enzyme Protease.
A
Protease works to break up the larger proteins which enhances the head retention of beer and reduces haze. In fully modified malts, these enzymes have done their work during the malting process.
7
Q
What is the optimum pH range for proteolytic enzymes during the mash?
A
optimum pH range is 4.2 - 5.3, and both enzymes are active enough between 113 - 131°F that talking about an optimum range for each is not relevant
8
Q
What is the standard amount of time for a Protein rest?
A
20-30 minutes
9
Q
What are the purposes of the enzymes beta-glucanases/cytases?
A
beta-glucanases/cytases - part of the cellulose enzyme family, and are used to break up the beta glucans in (un)malted wheat, rye, oatmeal and unmalted barley. These glucan hemi-celluloses (i.e. brambles) are responsible for the gumminess of dough and if not broken down will cause the mash to turn into a solid loaf ready for baking.
10
Q
What are amylases?
A
The amylases are enzymes that work by hydrolyzing the straight chain bonds between the individual glucose molecules that make up the starch chain.
11
Q
What is the temperature most often quoted for mashing?
A
153°F. This is a compromise between the two temperatures that the two enzymes favor. Alpha works best at 154-162°F, while beta is denatured (the molecule falls apart) at that temperature, working best between 131-150°F.
12
Q
What can the brewer use to check the conversion rate between starch to sugar?
A
The brewer can use iodine (or iodophor) to check a sample of the wort to see whether the starches have been completely converted to sugars. As you may remember from high school chemistry, iodine causes starch to turn black. The mash enzymes should convert all of the starches, resulting in no color change when a couple drops of iodine are added to a sample of the wort.
13
Q
What is the result of running a lower mash temperature, less than or equal to 150°F?
A
It yields a thinner bodied, drier beer.
14
Q
What is the result of running a higher mash temperature, greater than or equal to 156°F?
A
It yields a less fermentable, sweeter beer.
15
Q
What are two other factors besides temperature that affect the amylase enzyme activity?
A
grist/water ratio and pH.
16
Q
What levels of pH do beta and alpha amylase prefer?
A
Beta amylase is favored by a low wort pH, about 5.0. Alpha is favored by a higher pH, about 5.7.
17
Q
What are the drawbacks of running low pH level that is favored for beta amylase?
A
A beta-optimum wort is not a very fermentable wort, leaving a lot of amylopectin starch unconverted; alpha amylase is needed to break up the larger chains so beta can work on them.
18
Q
What are the drawbacks of running high pH level that is favored for alpha amylase?
A
an alpha-optimum wort will not have a high percentage of maltose but instead will have a random distribution of sugars of varying complexity.
19
Q
Why would a brewer add salt to the mash?
A
Brewing salts can be used to raise or lower the mash pH but these salts can only be used to a limited extent because they also affect the flavor.
Note: Malt selection can do as much or more to influence the pH as using salts in many situations.
20
Q
How do brewers test pH?
A
The pH of the mash or wort runnings can be checked with pH test papers sold at brewshops, and pool supply stores.
21
Q
A lower mash pH (near 5.2) has what benefits?
A
- Improved enzyme activity during the mash, leading to better conversion of starches to sugars.
- Lower pH in the finished wort which improves yeast health during fermentation, and also inhibits bacteria growth.
- Improved hop extraction rates in the boil.
- Better protein and polyphenol precipitation both during the cold break and post fermentation.
- Improved clarity in the finished beer with reduced chill haze.
- Improved flavor and clarity stability as the beer ages
22
Q
What are some sources that factor that affect the pH?
A
- Water Used: The chemical composition of the water is a large driver in mash pH. Calcium, magnesium, carbonates and bicarbonates are all drivers of mash pH. Most water sources are slightly alkaline, so they tend to drive the mash pH above the desired 5.2-5.4 range.
- Malts: Malts tend to be acidic, which means that they lower the mash pH of the overall mixture. Dark malts in particular can be very acidic, which is why many darker beers require little mash pH adjustment. Lighter malts have less buffering capability, so lighter beers often need additives covered blow to drive the mash pH down to the desired level. Unfortunately the acidity of malts varies widely and is not measured and published, so prediction of mash pH in advance is very difficult.
23
Q
If the pH in your mash is too high what can you add to lower it?
A
- Lactic Acid – An organic acid produced by bacteria. Many home brew stores sell it in liquid form that is about 88% by weight solution, though this does vary. It is added a little at a time until you reach your target pH.
- Acid Malt – This is typically pilsner malt that has been acidified using lactic acid and contains about 3% acid by weight. Acid malt is primarily used in Germany to comply with strict purity laws (Reinheitsgebot) that prohibit additions other than malt, water, yeast and hops to beer.
- Phosphoric Acid – An inorganic acid widely used in soft drinks. It replaces bicarbonate with phosphate and increases the phosphate content of the wort.
- Hydrochloric and Sulfuric Acid – Used by many commercial brewers, these acids are usually not widely available to the public.
- Buffers such as “5.2 Stabilizer” – These salts lower the mash pH by reacting with phosphates brought in by the malt. They can raise the hardness of the mash water in the process, but they are a great “fire and forget” alternative since you can often add a pre-measured amount of buffer to the mash and achieve the desired range.
24
Q
How do you avoid oversparging when brewing?
A
The most common method to avoid oversparging is to monitor the gravity of the runnings and stop sparging when the gravity falls below 1.008 for an average strength beer. Obviously that number would be higher or lower if brewing a very high gravity or low gravity beer. Some brewers with a pH meter also have the option of monitoring the pH of the runnings and stopping when the pH rises above 6.0.
25
What damage can occur when sparging with excessively hot water?
Sparging at excessively high temperatures can also result in astringency in the finished beer. Sparging at a moderately temperature has some benefits as it improves the flow of wort through the grain bed.
The maximum temperature for sparging is 170 F (77 C). Sparging above that can result in tannin extraction. Some people do use higher temperature sparge additions, but only to raise the temperature of the mash as a whole during the initial phase of the sparge. In no case do you want to raise the grain bed or runnings above 170 F (77 C).
26
What is a major benefit of bottle conditioning your beer?
The beer achieves a longer shelf-life because the yeast in the bottle consumes the oxygen.
27
How many gallons of beer is a home brewer allowed to brew?
Since 1979 it has been legal to homebrew up to 200 gallons of beer per family household.
28
Lautering can be conducted in several ways, but it usually consists of three steps. What are those 3 steps?
mash-out, recirculation, and sparging.
29
Define Mash-Out when brewing.
Mash-out is the first step during the lautering phase.
Mash-out is the term for raising the temperature of the mash to 170 F prior to lautering. This step stops all of the enzyme action (preserving the fermentable sugar profile) and makes the grain and wort more fluid.
30
Define the recirculation process when lautering.
Recirculation is the second phase of lautering.
Recirculation, also knows as the vorlauf step, occurs after the grain bed has settled and is ready to be lautered. The first few quarts of wort are drawn out through the drain of the lauter tun and poured back in on top of the grain. This helps settle the grain bed to ensure proper mash filtration and clarity.
31
Define the sparging process during lautering.
Sparging is the third process of lautering.
Sparging is the process of rinsing the grain bed that has settled at the bottom of the lauter tun in order to extract the remaining sugars. The temperature of the sparge water is carefully controlled so as not to also extract tannins from grain husks.
32
Discuss an Infusion Mash.
Infusion Mash
In this type of mash, crushed grains are added to water heated at one specific temperature within the range of a saccharification rest. The target mash temperature is then held for the entire period of the mash. This mash is most common when highly modified malts are used and low-protein malts are the dominant part of the grist (crushed grain).
33
List some reasons why we do a boil.
Boil
There are multiple reasons to boil wort, though it’s not done for all styles. Boiling:
-Stops enzymatic activity (no more conversion of starches to sugars), known as ‘denaturing’ enzymes.
- Blows off undesired volatile compounds including some hop oils, sulfur compounds and dimethyl sulfide (DMS).
- Encourages ‘hot break,’ which is a coagulation of proteins and tannins that improves beer’s clarity and decreases astringency.
- Concentrates wort through evaporation.
- Converts hop alpha acids into isomerized hop alpha acids that provide bitterness to beer.
- Kills off any microbes that may be in the wort, thus sterilizing it (note some microbes are favorable, but are commonly added post-boil as they cannot survive the heat).
34
What is Whirlpooling?
Whirlpool happens after the boil and serves to collect hop particulates and coagulated protein from the hot break. This often happens in a dedicated vessel, or can be done in the boil kettle. The beer is spun in a circular fashion, allowing particles (called ‘trub’) to collect together at the bottom center of the vessel. Then the wort is siphoned away, leaving the trub behind.
35
Why do we chill the wort after the boil?
Chilling
The wort is chilled to prepare it for fermentation. Methods of chilling include immersion chillers, which are set inside the wort, and heat exchangers that pass wort and cold water through a parallel set of coils, thereby cooling the hot wort indirectly. Beer is commonly chilled down to yeast-pitching temperature, which varies depending on yeast strain and the brewer’s intentions (usually 40-70 F).
36
What occurs during primary fermentation?
Primary fermentation is when the yeast is the most vigorous and active. As yeast consumes the fermentable malt sugars, it begins to settle to the bottom of the tank (a process called ‘flocculation’).
Secondary fermentation is when the initial yeast cake (dormant yeast at the bottom of the fermentor) has been removed and the beer continues to ferment at a slower pace. Beer also begins to clarify during this step.
37
When does conditioning occur and why?
Conditioning
Conditioning occurs when the yeast has stopped fermenting the wort and has finished settling out to the bottom of the fermentor. This is also the period when yeast byproducts such as diacetyl and acetaldehyde are lessened or completely removed. Note that these byproducts are acceptable at lower levels in some beer styles.
38
Why is carbonation so important in beer?
Carbonation
Carbonation, or CO2, is a main ingredient in beer. It lends body or weight on the tongue and stimulates the trigeminal nerves, which sense temperature, texture and pain in the face. Carbonation can be detected as an aroma (carbonic acid). It also affects appearance and is what creates the collar of foam common to most beer styles.
39
What are some ways carbonation can be introduced in beer?
Carbonation is introduced into beer in a variety of ways:
Natural carbonation: As yeast eats sugars during fermentation, it produces a variety of byproducts, including alcohol and CO2. This carbonation can be captured and used to carbonate the finished beer.
Force carbonation: One method of force carbonation is via a device called a carbonation stone. This device injects CO2 from a separate gas tank into beer that resides in a conditioning or serving vessel. It allows CO2 to dissolve into the beer.
Bottle conditioning: Addition of yeast at packaging time. This yeast, under the right conditions, will ferment residual sugars still left in the beer and then produce CO2 that disolves directly into the beer in the bottle. Successful bottle conditioning requires residual sugars and yeast to still be present in the beer. It is a common technique used by smaller brewers and homebrewers.
40
List the following brewing steps in the proper order:
- Fermentation
- Boil
- Mash
- Carbonation
- Lautering
- Whirlpool
- Conditioning
- Chilling
1. Mash
2. Lautering
3. Boil
4. Whirlpool
5. Chilling
6. Fermentation
7. Conditioning
8. Carbonation
41
What are the 3 categories hops fall into?
Hops used in beer generally fall into three categories: bittering, aroma and dual-purpose. Bittering hops contain more alpha acids and are used primarily to contribute bitterness, while aroma hops are used primarily to add flavor and aroma to beer. Dual-purpose hops can have higher alpha acid content, but also are used to contribute aroma compounds.
42
What is the typical range of alpha acid found in hops?
Alpha acid content of most hops ranges from 2 to 20 percent by weight.
43
What are the names of hops main essential oils?
Hops’ main essential oils influencing aroma and flavor are:
-Humulene (common in noble hops) · Woody/piney notes
-Myrcene (pungent; largest component of hop oil; can help indicate ripeness of hop cone)
· Green resin aromatics Caryophyllene
· Woody notes Farnesene
· Floral notes
These oils volatize off when exposed to heat, so aroma and flavor hops are added at the end of the boil or during or after fermentation (a technique referred to as “dry hopping”).
44
How does the pH scale work?
pH
pH measures the concentration of ions in a liquid. The pH scale runs from 0 (acidic) to 14 (alkaline), with 7 as the neutral midpoint.
• Acidic (0-6) has higher Hydrogen concentration
• Alkaline (8-14) has higher Hydroxide concentration
Just like the Richter scale for earthquakes, pH is logarithmic. Every point on the pH scale is ten times greater or lesser in concentration than the point above or below it. For example: pH 4 is 1,000 times (103 or 10 x 10 x 10) more acidic than pH 7.
45
How do Darker kilned malts affect the pH level?
Darker kilned and roasted malts decrease mash pH.
46
What does a high alkaline mash (above 5.7) offer to the mash?
Too alkaline a mash (above pH 5.7) lessens the chance for proper malt color extraction.
47
What does ideal mash pH ensure?
Ideal mash pH ensures:
-• Ideal enzyme conditions for proper saccrification (the conversion of malt starch into fermentable sugars, primarily maltose)
- No leaching of harsh tannins/polyphenols from malt husk
- Proper “hot break,” which aids in coagulation of proteins during the mash boil.
48
When dealing with a mash's pH, what does alkalinity determine?
Alkalinity determines the buffering capacity of water (the degree to which water will reduce the acidity of the beer). Calcium and magnesium affect hardness. Carbonates and bicarbonates affect alkalinity.
49
What are some ways brewers can lower the alkalinity in the pH level?
- Add dark malts to lessen pH to a more acidic environment.
- Use brewing salts
- Add acidic compounds like lactic acid or acidulated malt (malt that has already been soured with lactic acid)
- Do a sour mash (a particular mixture of grain and water that encourages the development of bacteria that produces lactic acid, which is present in the husk of the barley).
50
List the importance of having Calcium (Ca+2) in your beer
Calcium is the principal ion that determines water hardness and has a +2 charge. As it is in our own bodies, calcium is instrumental to many yeast, enzyme, and protein reactions, both in the mash and in the boil. It promotes clarity, flavor, and stability in the finished beer. Calcium additions may be necessary to assure sufficient enzyme activity for some mashes in water that is low in calcium. Calcium that is matched by bicarbonates in water is referred to as "temporary hardness". Temporary hardness can be removed by boiling. Calcium that is left behind after the temporary hardness has been removed is called "permanent hardness".
Brewing Range = 50-150 ppm.
51
List the importance of having Magnesium (Mg+2) in your beer.
Magnesium behaves very similarly to Calcium in water, but is less efficacious. It also contributes to water hardness. Magnesium is an important yeast nutrient in small amounts (10 -20 ppm), but amounts greater than 50 ppm tend to give a sour-bitter taste to the beer. Levels higher than 125 ppm have a laxative and diuretic affect.
Brewing Range = 10-30 ppm
52
List the importance of having Bicarbonate (HCO3-1) in your beer.
The carbonate family of ions are the big players in determining brewing water chemistry. Carbonate (CO3-2), is an alkaline ion, raising the pH, and neutralizing dark malt acidity. Its cousin, bicarbonate (HCO3-1), has half the buffering capability but actually dominates the chemistry of most brewing water supplies because it is the principal form for carbonates in water with a pH less than 8.4. Carbonate itself typically exists as less than 1% of the total carbonate/bicarbonate/carbonic acid species until the pH exceeds 8.4. There are two methods the homebrewer can use to bring the bicarbonate level down to the nominal 50 - 150 ppm range for most pale ales, or even lower for light lagers such as Pilsener. These methods are boiling, and dilution.
Brewing Range = 0-50 ppm for pale, base-malt only beers.
50-150 ppm for amber colored, toasted malt beers, 150-250 ppm for dark, roasted malt beers.
53
Discuss the two ways, boiling or dilution process, to bring down the bicarbonate levels in beer.
In boiling, carbonate can be precipitated (ppt) out as Calcium Carbonate (CaCO3) by aeration and boiling according to the following reaction:
2HCO3-1 + Ca+2 + O2 gas --> CaCO3 (ppt) + H2O + CO2 gas
where oxygen from aeration acts as a catalyst and the heat of boiling prevents the carbon dioxide from dissolving back into the water to create carbonic acid.
Dilution is the easiest method of producing low carbonate water. Use distilled water from the grocery store (often referred to as Purified Water for use in steam irons) in a 1:1 ratio, and you will effectively cut your bicarbonate levels in half, although there will be a minor difference due to buffering reactions. Bottom Line: if you want to make soft water from hard water (e.g. to brew a Pilsener), dilution with distilled water is the best route.
54
List the importance of having Sulfate (SO4-2) in your beer.
The sulfate ion also combines with Ca and Mg to contribute to permanent hardness. It accentuates hop bitterness, making the bitterness seem drier, more crisp. At concentrations over 400 ppm however, the resulting bitterness can become astringent and unpleasant, and at concentrations over 750 ppm, it can cause diarrhea. Sulfate is only weakly alkaline and does not contribute to the overall alkalinity of water.
Brewing Range = 50-150 ppm for normally bitter beers, 150-350 ppm for very bitter beers
55
List the importance of having Chloride (Cl-1) in your beer.
The chloride ion also accentuates the flavor and fullness of beer. Concentrations above 300 ppm (from heavily chlorinated water or residual bleach sanitizer) can lead to mediciney flavors due to chlorophenol compounds.
Brewing Range = 0-250 ppm.
56
What is the formula for figuring out your ABV in a beer?
```
To calculate the approximate volumetric alcohol content, subtract the final gravity from the original gravity and divide by 0.0075.
• Formula: ABV = (OG – FG) / 0.0075
• Example: OG 1.050, FG 1.012
- ABV = (1.050 – 1.012) / 0.0075
- ABV = 0.038 / 0.0075
- ABV = 5.067
- ABV = 5.1% (approximately)
```
57
International Bitterness Units (IBUs)
| • 1 bitterness unit = 1 milligram of ________________ in one liter of beer.
International Bitterness Units (IBUs)
| • 1 bitterness unit = 1 milligram of isomerized hop alpha acids in one liter of beer.
58
Describe an Infusion Mash
Infusion Mash:
In this type of mash, crushed grains are added to water heated at one specific temperature within the range of a saccharification rest. The target mash temperature is then held for the entire period of the mash. This mash is most common when highly modified malts are used, and low-protein malts are the dominant part of the grist (crushed grain).
59
Recirculation (aka. "Vorlauf")
Recirculation, also knows as the vorlauf step, occurs after the grain bed has settled and is ready to be lautered. The first few quarts of wort are drawn out through the drain of the lauter tun and poured back in on top of the grain. This helps settle the grain bed to ensure proper mash filtration and clarity.
60
Sparging
Sparging is the process of rinsing the grain bed that has settled at the bottom of the lauter tun in order to extract the remaining sugars. The temperature of the sparge water is carefully controlled so as not to also extract tannins from grain husks
61
Whirlpooling
Whirlpool happens after the boil and serves to collect hop particulates and coagulated protein from the hot break. This often happens in a dedicated vessel, or can be done in the boil kettle. The beer is spun in a circular fashion, allowing particles (called ‘trub’) to collect together at the bottom center of the vessel. Then the wort is siphoned away, leaving the trub behind.
62
Secondary fermentation
Secondary fermentation is when the initial yeast cake (dormant yeast at the bottom of the fermentor) has been removed, and the beer continues to ferment at a slower pace. Beer also begins to clarify during this step.
63
Darker kilned and roasted malts decrease mash pH. Too alkaline a mash (above pH 5.7) lessens the chance for proper malt color extraction. Ideal mash pH ensures:
Ideal mash pH ensures:
- Ideal enzyme conditions for proper saccrification (the conversion of malt starch into fermentable sugars, primarily maltose);
- No leaching of harsh tannins/polyphenols from malt husk;
- Proper “hot break,” which aids in coagulation of proteins during the mash boil.
64
What does Alkalinity determine?
Alkalinity determines the buffering capacity of water (the degree to which water will reduce the acidity of the beer). Calcium and magnesium affect hardness. Carbonates and bicarbonates affect alkalinity. Together they affect mash pH.
65
What do brewers do to lower Alkalinity?
To lower alkalinity, brewers:
• Add dark malts to lessen pH to a more acidic environment;
• Use brewing salts;
• Add acidic compounds like lactic acid or acidulated malt (malt that has already been soured with lactic acid);
• Do a sour mash (a particular mixture of grain and water that encourages the development of bacteria that produces lactic acid, which is present in the husk of the barley).
66
What does "hard water" mean?
Hardness is the concentration of minerals in water. Water high in calcium/magnesium and bicarbonate/sulfate is said to be ‘hard.’ Hard water is used in German-style Dunkels, German-style Marzen/Oktoberfest beers, Vienna-style Lagers, Irish-style Dry Stouts, Scottish-style Ales and English-Style Pale Ales/ESBs.
67
What makes the water in Burton-on-Trent so unique?
The presence of calcium sulfate (gypsum) enhances bitterness, but also can induce dryness and lend a low sulfitic character. This effect has been called the ‘Burton snatch,’ originating from beers made in Britain in the Burton-on-Trent area.
68
Ions in brewing water primarily affect pH and may add or accentuate certain flavors.
What are some positively charged ions (Cations) in beer?
Cations found in beer:
- Calcium is the most important ion for brewing. (Lowers mash pH)
- Magnesium (Lowers mash pH)
- Sodium (Flavor ion, lowers pH)
69
Ions in brewing water primarily affect pH and may add or accentuate certain flavors.
What are some negatively charged ions (Anions) found in beer?
Anions found in beer:
- Bicarbonate is the most important ion for alkalinity (1. Raises pH; 2.Reacts with calcium to reduce hardness during the boil.)
- Chloride (1. Increases mouthfeel; 2. Accentuates bitterness and dryness.)
70
Lager yeast
Lager: Saccharomyces pastorianus. Often lends sulfuric compounds. Commonly referred to as bottom-fermenting. Most often ferments at cooler temperatures (45-55°F).
71
Ale yeast
Ale: Saccharomyces cerevisiae. Generally produces more flavor compounds (esters). Commonly referred to as top- fermenting. Most often ferments at warmer temperatures (60-70°F).
72
What kind of ester creates a banana or pear note?
Isoamyl acetate (common from weizen ale yeast)
73
What kind of ester creates a nail polish remover or solvent note to a beer?
Ethyl Acetate
74
Common staling flavors include what?
Common staling flavors include: Almond, black currant, E-2-nonenal (Papery/cardboard), honey, metallic, sherry and more.
75
List the Color/Standard Reference Method (SRM) reading
Very Light (1-1.5), Straw (2-3), Pale (4), Gold (5-6), Light Amber (7), Amber (8), Medium Amber (9), Copper/Garnet (10-12), Light Brown (13-15), Brown/Reddish Brown/Chestnut Brown (16-17), Dark Brown (18-24), Very Dark (25-39), Black (40+)
76
Lag Phase
Lag Phase - The period of adaptation and rapid aerobic growth of yeast upon pitching to the wort. The lag time typically lasts from 2-12 hours.
77
Amino Acids
Amino Acids - An essential building block of protein, being comprised of an organic acid containing an amine group (NH2).
78
Amylose
Amylose - A straight-chain starch molecule found in the endosperm of barley.
79
Amylopectin
Amylopectin - A branched starch chain found in the endosperm of barley. It can be considered to be composed of amylose.
80
Autolysis
Autolysis - When yeast run out of nutrients and die, they release their innards into the beer, producing off-flavors.
81
Zymurgy
The science of brewing and fermentation.
82
Anaerobic
A process that does not utilize oxygen or may require the absence of it.
Brewing Beer
flashcards
Decks in class (1)
# Cards
