Information gathered from books and internet * A special thanks to John Palmer*
HISTORY OF MASHING
4300 BC: Babylonian clay tablets detail recipes for beer. The Babylonians were producing beer in large quantities with around 20 varieties.
“The Hymn to Ninkasi”
The artifact shown here, dating to 1800 BC, is etched with a hymn to Ninkasi, the goddess of brewing
Ninkasi, you are the one who handles the dough [and] with a big shovel,
Ninkasi, you are the one who bakes the bappir in the big oven,
Puts in order the piles of hulled grains,
Ninkasi, you are the one who waters the malt set on the ground,
Ninkasi, you are the one who soaks the malt in a jar,
Ninkasi, you are the one who spreads the cooked mash on large reed mats,
You place appropriately on a large collector vat.
Ninkasi, you are the one who pours out the filtered beer of the collector vat,
“Sounds like malting and mashing to me”
6 Row & 2 Row Barley
Barley Malt Defined
Malted barley is the source of the sugars (principally maltose) which are fermented into beer. The malting process allows the grain to partially germinate, making the seed’s resources available to the brewer. During germination enzymes in the aleurone layer (Figure 69) are released, and new enzymes are created, that break down the endosperm’s protein/carbohydrate matrix into smaller carbohydrates, amino acids and lipids, and open up the seed’s starch reserves. The endosperm is composed of large and small starch granules that are packed like bags of jellybeans in a box. The cell walls (bags) within the matrix holding the starch granules (jellybeans) are primarily composed of beta-glucans (a type of cellulose), some pentosans (gummy polysaccharide) and some protein. The box in this metaphor is the outer husk. The degree to which the enzymes tear open the cell walls and start unpacking the starch granules (is referred to as the “modification.”
One visual indicator that a maltster uses to judge the degree of modification is the length of the acrospire which grows underneath the husk. The length of the acrospire in a fully modified malt will typically be 75-100% of the seed length.
The purpose of malting is to create these enzymes, break down the matrix surrounding the starch granules, prepare the starches for conversion, and then stop this action until the brewer is ready to utilize the grain. After modification, the grain is dried and the acrospire and rootlets are knocked off by tumbling. The kiln drying of the new malt denatures (destroys) a lot of the different enzymes, but several types remain, including the ones necessary for starch conversion. The amount of enzymatic starch conversion potential that a malt has is referred to as its “diastatic power”.
From a brewer’s point of view, there are basically two kinds of malted grain, those that need to be mashed and those that don’t. Mashing is the hot water soaking process that provides the right conditions for the enzymes to convert the grain starches into fermentable sugars
There are two different original gravities (OG) that matter to a brewer: one is the pre-boil or extraction OG, and the other is the post-boil or pitching OG. And, ninety percent of the time, the pitching OG is what people are referring to because it determines the strength of the beer. When brewers plan recipes, they think in terms of the pitching OG, which assumes that the wort volume is the final size of the batch, e.g. 5 gallons.
But, when it comes to the efficiency of the mash and lauter, we want to think in terms of the pre-boil gravity. The Extract Efficiency section and table gave us the typical malt yields that allows us to evaluate our mashing process.
When all-grain homebrewers get together to brag about their brewing prowess or equipment and they say something like, “I got 30 (ppg) from my mash schedule”, they are referring to the overall yield from their mash in terms of the amount of wort they collected.
It is important to realize that the total amount of sugar is constant, but the concentration (i.e. gravity) changes depending on the volume. To understand this, let’s look at the unit of points/pound/gallon. This is a unit of concentration, so the unit is always expressed in reference to 1 gallon (“per gallon”). In mashing, you are collecting “x” number of gallons of wort that has a gravity of “1.0yy” that was produced from “z” pounds of malt. To calculate your mash extraction in terms of ppg, you need to multiply the number of gallons of wort you collected by its gravity and divide that by the amount of malt that was used. This will give you the gravity (points per gallon) per pound of malt used. Let’s look at an example.
Palmer’s Short Stout (target OG = 1.050) Malts 6.5 lbs. of 2 Row 0.5 lb. of Chocolate Malt 0.5 lb. of Crystal 60 0.5 lb. of Dextrin Malt 0.5 lb. of Roast Barley (8.5 lbs. total)
For our example batch, we will assume that 8.5 pounds of malt was mashed to produce 6 gallons of wort that yielded a gravity of 1.038. The brewer’s total sugar extraction for this batch would be 6 gallons multiplied by 38 points/gallon = 230 points. Dividing the total points by the pounds of malt gives us our mash extraction in points/pound e.g. 230/8.5 = 27 ppg. This value is good, if not great; 30 ppg is basically what everyone shoots for. Comparing these numbers to lager malt’s 37 ppg maximum gives us a good approximation of our mash efficiency: 27/37 = 73%, while 30/37 = 81%.
If we look at the maximum ppg numbers from Table 9 for each of the recipe’s malts, we can calculate our actual mash efficiency:
|Malts||OG based on Max. PPG|
|6.5 lbs. of 2 Row||37 x 6.5 / 6 = 40.1|
|0.5 lb. of Chocolate Malt||28 x .5 / 6 = 2.3|
|0.5 lb. of Crystal 60||34 x .5 / 6 = 2.8|
|0.5 lb. of Dextrin Malt||32 x .5 / 6 = 2.6|
|0.5 lb. of Roast Barley||25 x .5 / 6 = 2.1|
In this case, our mash extraction of 1.038 means our percent efficiency was 38/49.9 = 76%. Usually I think you will find that your efficiency will be 80% or better.
Table 9 – Typical Malt Yields in Points/Pound/Gallon
|Malt Type||Max. Yield||Max. PPG||Typical PPG (85%)||PPG Steep|
|2 Row Lager Malt||80||37||31||–|
|6 Row Base Malt||76||35||30||–|
|2 Row Pale Ale Malt||81||38||32||–|
|Light Crystal (10 – 15L)||75||35||30||14*|
|Pale Crystal (25 – 40L)||74||34||29||22|
|Medium Crystal (60 – 75L)||74||34||29||18|
|Dark Crystal (120L)||72||33||28||16|
|Black Patent Malt||55||25||22||21|
|Malto – Dextrin Powder||100||40||(40)||(40)|
|Sugar (Corn, Cane)||100||46||(46)||(46)|
Malt % Yield data obtained and averaged from several sources. Steeping data is experimental and was obtained by steeping 1 lb. in 1 gal at 160°F for 30 minutes. All malts were crushed in a 2 roller mill at the same setting. * The low extraction from steeping is attributed to unconverted, insoluble starches as revealed by an iodine test.
How the Mash Makes Wort –John Palmer
• Mashing Defined
• The Acid Rest and Modification
• The Protein Rest
• The Starch Conversion/Saccharification Rest
• Manipulating the Starch Conversion Rest
Mashing is the brewer’s term for the hot water steeping process which activates the malt enzymes and converts the grain starches into fermentable sugars. There are several key enzyme groups that take part in the conversion of the grain starches to sugars. When mashing malted grain, the brewer is concerned with two main classes of enzymes: proteases (or proteolytic enzymes), and diastases (or diastatic enzymes). Proteolytic enzymes break down long complex chains of protein molecules into simpler and more useful proteins and amino acids. Diastatic enzymes convert starch molecules into fermentable sugars and unfermentable dextrins. Each of these enzymes is favored by different temperature and pH conditions. A homebrewer can adjust his or her mash temperature to favor each successive enzyme’s function and thereby customize the wort to their taste.
The starches in the mash are about 90% soluble at 130 °F and reach maximum solublity at 149°F. Unmalted grains have their starch reserves locked in a protein matrix which prevents the enzymes from being able to physically contact the starches for conversion. Only by crushing or rolling the grains is the matrix broken up. The starches can be gelatinized (made soluble) by heat alone or by a combination of heat and enzyme action. Either way, a mash is needed to convert the soluble starches to fermentable sugars.
Figure 11 – Typical Enzyme Ranges in the Mash
|Enzyme||Optimum Temp Range||Optimum pH Range||Function|
|Phytase||86 – 126°F||4.4 – 5.5||Lowers the Mash pH. No longer used.|
|Beta Glucanase||98 – 113°F||4.5 – 5.0||Best gum breaking rest.|
|Peptidase||115 – 135°F||4.6 – 5.2||Produces Free Amino Nitrogen (FAN).|
|Protease||115 – 135°F||4.6 – 5.2||Breaks up large proteins that form haze|
|Beta Amylase||130 – 150°F||5.0 – 5.6||Produces small, highly fermentable sugars.|
|Alpha Amylase||155 – 167°F||5.3 – 5.8||Produces larger, less fermentable sugars|
Note: The above numbers were averaged from several sources and should be interpreted as typical optimum activity ranges. The enzymes will be active outside the indicated ranges but will be destroyed as the temperature increases above each range.
Doughing-In/ The Acid Rest To the best of my knowledge, this temperature rest (holding period) is no longer used by any commercial brewery. It is sometimes used by homebrewers for “Doughing In”- mixing the grist in with the water to allow time for the mash to liquify and time for the enzymes to be distributed. The use of the a 20 minute rest at temperatures near 100°F (40°C) has been shown to be beneficial to improving the yield from all enzymatic malts. This step is considered to be optional but can improve the total yield by a couple of points.
The Protein Rest and Modification Modification is a term which describes the degree of breakdown during malting of the protein-starch matrix (endosperm) that comprises the bulk of the seed. Moderately-modified malts (6 Row Barley) need a protein rest to utilize the proteolytic enzymes that are responsible for breaking down the large proteins into smaller proteins and amino acids as well as the beta-glucanases/cytases to release the starches from the endosperm. Fully-modified malts( 2 Row Barley) have 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. Less modified malts are often available from German maltsters. Brewers have reported fuller, maltier flavors from malts that are less modified and make use of this rest.
Malted barley also contains a lot of amino acid chains which form the simple proteins needed by the germinating plant. In brewing, these proteins are instead utilized by the yeast for their growth and development. The two main proteolytic enzymes responsible are peptidase and protease. Peptidase works to provide the wort with amino acid nutrients that will be used by the yeast. 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.
The temperature and pH ranges for these enzymes overlap. The optimum pH range is 4.6 – 5.2 and both enzymes are active enough between 115 – 135°F that talking about an optimum range for each is not relevant. This optimum pH range is a bit low with respect to most mashes, but the typical mash pH of 5.3 is not out of the ballpark. There is no need to attempt to lower the mash pH to facilitate the use of these enzymes. The typical Protein Rest at 125 – 130°F is used to break up the proteins which might otherwise cause chill haze and can improve the head retention in beers made from lightly kilned and/or less-modified malts. The standard time for a protein rest is 20 – 30 minutes. If the rest is too long, the head retention and body of the beer will be diminished. This rest should only be used when using moderately-modified barley malts, or a large proportion (>25%) of flaked barley, wheat, rye, or oatmeal. Otherwise there is usually no need with today’s fully-modified malts.
The other enzyme in this temperature regime is glucanase- part of the starch enzyme family, and is used to break up the beta glucans in (un)malted wheat, rye, oatmeal and unmalted barley. These glucan hemi-celluloses 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. Fortunately, the optimum temperature range for the beta glucanase enzyme is below that for the proteolytics. This allows the brewer to rest the mash at 98 -113°F for 20 minutes to break down the gums without affecting the proteins responsible for head retention and body. The use of this rest is only necessary for brewers incorporating a large amount (>25%) of unmalted or flaked wheat, rye or oatmeal in the mash. Sticky mashes and lauters from lesser amounts can usually be handled by increasing the temperature at lautering time (Mashout). See Chapter 17 – “Getting the Wort Out – Lautering” for further discussion.
Starch Conversion / Saccharification Rest In this stage the diastatic enzymes start acting on the starches, breaking them up into sugars (hence the term saccharification). One group, the amylases, are enzymes that work on the more complex starches and sugars. The two main amylases are Alpha and Beta. Alpha works by breaking up long, branched starch chains at the branch points, leaving behind a variety of straight chain starches and dextrin-type sugars. The reduction of these large branched chains reduces the viscosity and “liquifies” the mash. Beta amylase works by separating these straight chains into fermentable maltose sugar units.
The temperature most often quoted for mashing is about 153°F. This is a compromise between the two temperatures that the two enzymes favor. Alpha works best at 158F, while beta is denatured (the molecule falls apart) at that temperature, working best at 140F. The mash liquification function of alpha amylase is effective at temperatures as low as 120°F.
What do these two enzymes and temperatures mean to the brewer? The practical application of this knowledge allows the brewer to customize the wort in terms of its fermentability. A lower mash temperature, less than or equal to 150F, yields a thinner bodied, drier beer. A higher mash temperature, greater than or equal to 158F, yields a less fermentable, sweeter beer. This is where a brewer can really fine tune a wort to best produce a particular style of beer.
Testing Your Conversion 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. (The wort sample should not have any grain particles in it.) The iodine will only add a slight tan or reddish color as opposed to the flash of heavy black color if starch is present. Worts high in dextrins will yield a strong reddish color when iodine is added.
The grist/water ratio is another factor influencing the performance of the mash. A thinner mash of >2 quarts of water per pound of grain dilutes the relative concentration of the enzymes, slowing the conversion, but ultimately leads to a more fermentable mash because the enzymes are not inhibited by a high concentration of sugars. A stiff mash of <1.25 quarts of water per pound is better for protein breakdown, and results in a faster overall starch conversion but the resultant sugars are less fermentable and will result in a sweeter, maltier beer. A thicker mash is more gentle to the enzymes because of the lower heat capacity of grain compared to water. A thick mash is better for multirest mashes because the enzymes are not denatured as quickly by a rise in temperature.
As always, time changes everything; it is the final factor in the mash. Starch conversion may be complete in only 30 minutes, so that during the remainder of a 60 minute mash, the brewer is working the mash conditions to produce the desired profile of wort sugars. Depending on the mash pH, water ratio and temperature, the time required to complete the mash can vary from under 30 minutes to over 90. At a higher temperature, a stiffer mash and a higher pH, the alpha amylase is favored and starch conversion will be complete in 30 minutes or less. Longer times at these conditions will allow the beta amylase time to breakdown more of the longer sugars into shorter ones, resulting in a more fermentable wort, but these alpha-favoring conditions are deactivating the beta; such a mash is self-limiting.
Summary A compromise of all factors yields the standard mash conditions for most homebrewers: a mash ratio of about 1.5 quarts of water per pound grain, pH of 5.3, temperature of 153-155F and a time of about one hour. These conditions yield a wort with a nice maltiness and good fermentability.
METHODS OF MASHING
All the cruched mast is mixed with hot water to achieve a mash temperature of 150º to 155º, depending on the type of beer being made for about one hour. Mashing at the lower temperature range will make a drier beer (more usgar converted to alcohol). Mashing at the higher temperature will produce a fuller body beer ( more dextrin’s)
A popular multi-rest mash schedule is the 40°C – 60°C – 70°C (104 – 140 – 158°F) mash, using a half hour rest at each temperature. This mash schedule produces high yields and good fermentability. The time at 40°C improves the liquefaction of the mash and promotes enzyme activity. As can be seen in Figure 79 – Enzyme Ranges, several enzymes are at work, liquefying the mash and breaking down the starchy endosperm so the starches can dissolve. As mentioned in the previous chapter in the section on the Acid Rest, resting the mash at this temperature has been show to improve the yield, regardless of the malts used. Varying the times spent at the 60 and 70°C rests allows you to adjust the fermentable sugar profiles. For example, a 20 minute rest at 60°C, combined with a 40 minute rest at 70°C produces a sweet, heavy, dextrinous beer; while switching the times at those temperatures would produce a drier, lighter bodied, more alcoholic beer from the same grain bill.
If you use less well-modified malts, such as German Pils malt, a multi-rest mash will produce maltier tasting beers although they need a protein rest to fully realize their potential. In this case the mash schedule suggested by Fix is 50 – 60 – 70°C, again with half hour rests. The rest at 50°C takes the place of the liquefaction rest at 40°C and provides the necessary protein rest. This schedule is well suited for producing continental lager beers. These schedules are provided as guidelines. You, as the brewer, have complete control over what you can choose to do. Play with the times and temperatures and have fun.
Multi-rest mashes require you to add heat to the mash to achieve the various temperature rests. You can add the heat in a couple of ways, either by infusions or by direct heat. If you are using a kettle as a mash tun, you can heat it directly using the stove or a stand-alone hotplate. The first temperature rest is achieved by infusion as in the Single Temperature mash described above. The subsequent rest(s) are achieved by carefully adding heat from the stove and constant stirring to keep the mash from developing hotspots and scorching. The mash can be placed in a pre-warmed oven (125 – 150 °F) to keep the mash from losing heat during the rests. After the conversion, the mash is carefully poured or ladled from the mash tun into the lauter tun and lautered. The hot mash and wort is susceptible to oxidation due to hot side aeration (HSA) due to splashing at this stage, which can lead to long term flavor stability problems.
In decoction mashing, a portion of the mash is removed from the mash tun and is transferred to a boiling pot. This portion is called the decoction, and it is heated slowly to bring it to a boil. After boiling for a period of time the decoction is added back to the main mash, thereby raising it’s temperature. In this respect, the decoction mash is similar to the step mash or temperature controlled mash. For example, the initial mash temperature and volume of the decoction can be chosen so that the temperature rise goes from the protein rest temperature to the sacharification rest (starch conversion) temperature. This would be called a single decoction mash because only one decoction was made. An additional decoction can be made to raise the mash temperature again to mash out (double decoction) or a total three decoctions (triple decoction) could be used to achieve an acid rest – protein rest – sacharification rest – mash out profile.
BIAB Brew in a Bag
Brew in a Bag (BIAB) all grain beer brewing is a new method for all grain brewing that originated in Australia. BIAB is an inexpensive way to for homebrewers to transition to all grain or partial mash brewing. Brewers also enjoy brew in a bag methods for the shorter setup, brewing and cleanup times.
The concept behind “brew in a bag” is to move to all grain brewing with minimal extra equipment, setup or time. The BIAB method involves using a grain bag set in the brew pot to mash the grains, followed by a no-sparge step where the bag is removed from the pot and the remaining wort is boiled as you would any other beer.
Before the sweet wort is drained from the mash and the grain is rinsed (sparged) of the residual sugars, many brewers perform a mashout. Mashout 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 your fermentable sugar profile) and makes the grainbed and wort more fluid. For most mashes with a ratio of 1.5-2 quarts of water per pound of grain, the mashout is not needed. The grainbed will be loose enough to flow well. For a thicker mash, or a mash composed of more than 25% of wheat or oats, a mashout may be needed to prevent a Set Mash/Stuck Sparge. This is when the grain bed plugs up and no liquid will flow through it. A mashout helps prevent this by making the sugars more fluid; like the difference between warm and cold honey. The mashout step can be done using external heat or by adding hot water according to the multi-rest infusion calculations. (See chapter 16.) A lot of homebrewers tend to skip the mashout step for most mashes with no consequences.
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 grainbed. The first few quarts are almost always cloudy with proteins and grain debris and this step filters out the undesired material from getting in your boiling pot. The wort should clear fairly quickly. After the worts starts running clear (it will be dark and a little bit cloudy), you are ready to collect the wort and sparge the grainbed. Re-circulation may be necessary anytime the grain bed is disturbed and bits of grain and husk appear in the runoff.
Sparging is the rinsing of the grain bed to extract as much of the sugars from the grain as possible without extracting mouth-puckering tannins from the grain husks. Typically, 1.5 times as much water is used for sparging as for mashing (e.g., 8 lbs. malt at 2 qt./lb. = 4 gallon mash, so 6 gallons of sparge water). The temperature of the sparge water is important. The water should be no more than 170°F, as husk tannins become more soluble above this temperature, depending on wort pH. This could lead to astringency in the beer.
The wort should be drained slowly to obtain the best extraction. Sparge time varies depending on the amount of grain and the lautering system, .5 – 2.5 hours. Sparging means “to sprinkle” and this explains why you may have seen or heard discussion of “sparge arms” or sprinklers over the grain bed for lautering. There is no reason to fool with such things. There are three main methods of sparging: English, batch and continuous.
In the English method of sparging, the wort is completely drained from the grain bed before more water is added for a second mash and drained again. These worts are then combined. Alternatively, the first and second runnings are often used to make separate beers. The second running is lighter in gravity and was traditionally used for making a Small Beer, a lighter bodied, low alcohol beer suitable for high volume quaffing at mealtimes.
Batch Sparging is a U.S. homebrewing practice where the full volume of sparge water is mixed into the mash. The grain bed is allowed to settle, and then the wort is drained off. The re-circulation step in this process takes place in the first minutes of the sparge. You can use more than one batch of water if you need to. This method differs from the English method in that the mash is not held for any significant time at the saccharification temperature before draining.
Continuous Sparging usually results in better extractions. The wort is re-circulated and drained until about an inch of wort remains above the grain bed. The sparge water is gently added, as necessary, to keep the fluid at least at that level. The goal is to gradually replace the wort with the water, stopping the sparge when the gravity is 1.008 or when enough wort has been collected, whichever comes first. This method demands more attention by the brewer, but can produce a higher yield.
ESTIMATING WATER VOLUME OF MASH
This table is a guide to estimate the amount of mash water to have for the BOIL.
Absorption and Evaporation during the mashing and boil process require more water volume to result in the finish volume of wort , ready for pitching of the yeast.
10 lb Total Grain Bill
|5 Gallon Finish Volume||5|
|.10 gal. Per pound of grain (.10×10) for grain absorption||1|
|.5 / 1 gal. For Evaporation (varies with length of boil)||.5|
|.25 gal. For Sediments||.25|
|Starting Volume of Water||6.75 Gallons|