Section 3 – Brewing All-Grain Beer
Chapter 17 - Getting the Wort Out
Okay, let’s see where we are:
We have discussed the different types of grain and how they can be used, we have talked about the mash enzymes and how they are affected by temperature and pH, and we have learned how the brewing water and grainbill combine to determine the mash pH and how we can manipulate it. In the last chapter, we moved from the chemical aspects of the mash to the physical. We learned about the basic methods of conducting a mash and producing the wort. In this chapter, we are going to discuss how we separate the malt sugars from the grain.
A Good Crush Means Good Lautering
[figure 101 – crushed grain]
There is a trade-off between particle size and extraction efficiency when mashing crushed grain. Fine particles are more readily converted by the enzymes and achieve the anticipated yield sooner. However, if all the grain were finely ground you would end up with porridge that could not be lautered. Coarse particles allow for good fluid flow and lautering but are not converted as well by the enzymes. A good crush has a range of particle sizes that allows for a compromise between extraction and lautering. If you look back at the discussion of malt analysis sheets in Chapter 12, we discussed how the extract of a malt is gauged according to two conditions: fine grind and coarse grind. The degree to which a malt is ground does have an effect on the speed of starch conversion by the enzymes, but only a small effect on the total amount of extract. Usually there is only a 1% difference between the ASBC Congress Mash values for fine grind and coarse grind. [figure 102 - Fine/Coarse comp.jpg]
A good crush is essential for getting the best mash efficiency and extraction. You need to thoroughly crush the endosperm while leaving the husks as intact as possible. You can get the grain crushed at the brewshop or buy a mill to crush it at home. There are two basic kinds of grain mill commercially available today. (Author's note, 2025: Nobody uses a Corona mill anymore.) The first is a Corona corn mill that uses two counter-rotating disks to grind the malt. It is actually intended to grind corn into corn meal, not for crushing malt for brewing. Setting the gap between the plates too close will result in barley flour and shredded husks, which is not good for lautering purposes—often leading to a stuck sparge. This type of grain mill can produce a reasonable crush without too much husk damage if the spacing is set properly (.035–.042 inch). It is the least expensive kind of mill, but I really don’t recommend getting one except for grinding adjuncts. [figure 103 – picture of maltmill]The other type of grain mill crushes the malt between two rollers like a clothes wringer. There is much less damage to the husks this way, which helps keep the wort flowing easily during the sparge. Roller mills are available in several configurations, with either fixed or adjustable gap settings, and will give a better, more consistent crush than a Corona type mill. The insoluble grain husks are very important for a good lauter. The grain bed forms its own filter from the husk and grain material. The husks allow water to flow through the bed—extracting the sugar, and prevent the grain bed from compacting. The wort is drawn out through the bottom of the bed by means of a false bottom or manifold, which have openings that allow the wort to be drawn off, but prevent the grain from being sucked in as well. Usually these openings are narrow slots, or holes up to an eighth of an inch in diameter. Let me repeat: the grain bed is the filter, the false bottom or manifold underneath only serves to distribute the wort collection points and keep the grain in the grain bed. If you use too fine a screen or slots, the fine particles will actually collect there and block flow, something I learned the hard way. Note: You may want to add rice hulls to the mash to help with lautering. The husk of malted barley constitutes about 5% of the weight, so if you are adding 20% malted wheat (which has no husk) in your brew, you would want to add at least 1% of the total grain bill weight in rice hulls to make up for it. Rice hulls are probably going to be necessary with wheat beers, rye beers, and high adjunct beers like American lager. The corn and rice don’t have the beta glucan that makes lautering difficult, but the high proportion of no-hulls will affect the lauterability all the same. I have not needed rice hulls for oatmeal stouts.
There is a trade-off between particle size and extraction efficiency when mashing crushed grain. Fine particles are more readily converted by the enzymes and achieve the anticipated yield sooner. However, if all the grain were finely ground you would end up with porridge that could not be lautered. Coarse particles allow for good fluid flow and lautering but are not converted as well by the enzymes. A good crush has a range of particle sizes that allows for a compromise between extraction and lautering. If you look back at the discussion of malt analysis sheets in Chapter 12, we discussed how the extract of a malt is gauged according to two conditions: fine grind and coarse grind. The degree to which a malt is ground does have an effect on the speed of starch conversion by the enzymes, but only a small effect on the total amount of extract. Usually there is only a 1% difference between the ASBC Congress Mash values for fine grind and coarse grind. [figure 102 - Fine/Coarse comp.jpg]
A good crush is essential for getting the best mash efficiency and extraction. You need to thoroughly crush the endosperm while leaving the husks as intact as possible. You can get the grain crushed at the brewshop or buy a mill to crush it at home. There are two basic kinds of grain mill commercially available today. (Author's note, 2025: Nobody uses a Corona mill anymore.) The first is a Corona corn mill that uses two counter-rotating disks to grind the malt. It is actually intended to grind corn into corn meal, not for crushing malt for brewing. Setting the gap between the plates too close will result in barley flour and shredded husks, which is not good for lautering purposes—often leading to a stuck sparge. This type of grain mill can produce a reasonable crush without too much husk damage if the spacing is set properly (.035–.042 inch). It is the least expensive kind of mill, but I really don’t recommend getting one except for grinding adjuncts. [figure 103 – picture of maltmill]The other type of grain mill crushes the malt between two rollers like a clothes wringer. There is much less damage to the husks this way, which helps keep the wort flowing easily during the sparge. Roller mills are available in several configurations, with either fixed or adjustable gap settings, and will give a better, more consistent crush than a Corona type mill. The insoluble grain husks are very important for a good lauter. The grain bed forms its own filter from the husk and grain material. The husks allow water to flow through the bed—extracting the sugar, and prevent the grain bed from compacting. The wort is drawn out through the bottom of the bed by means of a false bottom or manifold, which have openings that allow the wort to be drawn off, but prevent the grain from being sucked in as well. Usually these openings are narrow slots, or holes up to an eighth of an inch in diameter. Let me repeat: the grain bed is the filter, the false bottom or manifold underneath only serves to distribute the wort collection points and keep the grain in the grain bed. If you use too fine a screen or slots, the fine particles will actually collect there and block flow, something I learned the hard way. Note: You may want to add rice hulls to the mash to help with lautering. The husk of malted barley constitutes about 5% of the weight, so if you are adding 20% malted wheat (which has no husk) in your brew, you would want to add at least 1% of the total grain bill weight in rice hulls to make up for it. Rice hulls are probably going to be necessary with wheat beers, rye beers, and high adjunct beers like American lager. The corn and rice don’t have the beta glucan that makes lautering difficult, but the high proportion of no-hulls will affect the lauterability all the same. I have not needed rice hulls for oatmeal stouts.
Yield Comparison
How does the degree of crushing affect the extraction? When new all-grain brewers complain on the forums that their yield from their mash was low, the experienced brewers often point to the crush. Did they buy the malt pre-crushed? Did they crush it themselves. Was it coarse? Was it crushed at all? (It happens.)
Increasing the degree of crush can significantly improve the yield from home mashing systems. It doesn’t have much effect on the results from an ASBC congress mash (fine/coarse difference typically ~1%). Why the difference in response? The ASBC method mashes a small sample of malt for two hours in a multi-rest mash. It is then lautered for another 1-2 hours! Homebrewers are diehards if they spend half that much time on ten pounds of malt.
I conducted an experiment with the help of Briess Malting Co. We compared the maximum extract values for four different grinds of the same lot of malt. I was hoping to show the difference in yield that homebrewers usually experience with their systems compared to commercial brewers and the coarse grind numbers on malt analysis sheets. The extraction results and the particle size assay (sieve analysis) for fine grind, coarse grind, 1 pass and 2 passes thru a homebrewing two roller mill are shown in Tables 24 and 25.
It’s interesting that the values are all within 1% of each other. This level of variation is not significant. In other words, the difference in yield is not necessarily due to the difference in the particle size distribution, but may simply be due to normal measurement error. Statistically, all the values could be the same, but we don’t have enough data here to prove it.So how can we account for the difference in homebrewer yields with differences in crush? Based on what I have read in professional brewing journals and discussed with professional brewers, I think the difference is in the efficacy of the mashing and lautering process. There is a trade-off between the crush size, the time required to achieve starch conversion, and the time required to lauter to get that extract out. Allow me to illustrate with two anecdotes.
Bob Hansen, the Manager of Technical Service at Briess Malting Co. tells me:“I often tell craft brewer's that they should relax their grind because the small difference they get by fine grinding can keep them lautering so long that there is no savings in term of time. For craft brewers, where labor/barrel is very high and most people are overworked, it's a no-brainer. I'm not sure they believe the guy who works for the malting company though, when he says "grind coarser and use more malt, but go home a half an hour earlier, it will be cheaper in the long run."
Don Obenauer, designer of the Crankandstein 2 and 3 roller mills, tells me:“…the best crushes might theoretically look like fine grinds. Yet in practice, and in ASBC recommendations, the sieve tests show that most brewer’s, especially hobbyists, prefer medium to coarse grinds that reduce the likelihood of stuck mashes and recirculations. This discrepancy is reflected in our funny story, though tragic to the all-too-experienced, multi-award winning Homebrewer of the Year who sieve tested a Crankandstein three-roller mill at his local microbrewery and came to the conclusion that running the grain through twice gave the ideal textbook result. He went home and ended up with a 45 lb. stuck sparge even after being warned not to blindly trust the screen results. His pipe-with-a-stainless-mesh-screen sparger (sic) turned into a straw full of concrete, and the whole mess got dumped. Next time the single pass at the factory setting worked just fine.”
The Lautering Process
Lautering is the method of separating the sweet wort from the mash. A lauter tun consists of a large vessel to hold the mash and a false bottom or manifold to allow the wort to drain out, while leaving the grain behind. Lautering can be conducted several ways, but it usually consists of three steps: mashout, recirculation, and sparging.
What is Mashout?
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 grain bed 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 grain bed 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. If your mash has lost a lot of heat during the mash and dropped below 140°F (60°C), beta-glucans, pentosans, and any unconverted starches will turn gummy and make very lautering difficult. 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. (I usually don’t do one, although if you are having lautering problems, it’s the first thing to try.)
What is Recirculation?
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 bed. This is also known as the vorlauf step. The first few quarts are always cloudy with proteins and grain debris and this step filters out the undesired material from getting into your boiling pot. The wort should clear fairly quickly. After the worts starts running clear (it will still be dark and a little bit cloudy, but chunk free), you are ready to collect the wort and sparge the grain bed. Re-circulation may be necessary anytime the grain bed is disturbed and bits of grain and husk appear in the runoff, though if your grain bed has good depth, disturbing it is unlikely.
What is Sparging?
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. Sparging means “to sprinkle” and you may have seen “sparge arms” or sprinklers in the lauter tuns of commercial breweries. In commercial breweries, the lauter tun is separate from the mash tun, and it is fitted with rakes and sprinkling systems to ensure that every useful gallon of extract is rinsed from the grain. On a homebrewing scale, we don’t need to be that economical, in fact, the smaller scale makes it easier to rinse the grain bed of the wort. 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 up to 6 gallons of sparge water). The temperature of the sparge water is important. The water should be no more than 170°F (77°C) as husk tannins become more soluble above this temperature, especially when the wort pH gets to 6 or above. This will lead to astringency in the beer. But it shouldn’t be much less than 170°F either (i.e., 165°F or 74°C). You want good fluidity. There are several sparging methods practiced by homebrewers.
Continuous Sparging
Also known as fly sparging, this method usually results in the best yield. The wort is re-circulated and drained until about an inch of wort remains above the grain bed. The sparge water is slowly added as the wort is drained. Sparge time varies (.5–2.5 hours) depending on the amount of grain and the type of collection system. The yield is highly dependent on the uniformity of fluid flow thru the grain bed to ensure that every grist particle is fully rinsed. The sparge is stopped when the gravity from the runnings 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 per pound of malt.
Parti-Gyle
This brewing method was common in England before the 19th century, and it allows you to make two beers from the same mash. A large mash is produced and the first wort is drained completely before more water is added to the grist for a second mash and drained again. The first and second runnings are used to make separate beers. The first runnings typically had a gravity of about 1.080 and were used for making an “aging” beer. The second runnings were lighter in gravity and used for making a “running” or table beer, and the mash was often “capped” with some additional grain strewn onto the grain bed to produce a low gravity small beer. Depending on the amount of grain in your mash, you can brew a barley wine and a pale ale, or a strong ale and a mild using this method. The first runnings is typically one third of the total wort volume for the batch and twice the gravity of the second runnings.
Batch Sparging
This method is a U.S. homebrewing practice where large volumes of sparge water are added to the mash all-at-once, instead of gradually, and is most often used with the large chest coolers. The grain bed is allowed to settle, re-circulated for clarity, and then the wort is drained off. Usually two or sometimes three sparges are combined to create the wort. This method differs from the English method in that the different runnings are combined to produce a single beer. This method was originally developed from parti-gyle to make large quantities of porter, and was known as “entire”. It is less efficient than continuous sparging (you will use 10-15% more grain than a continuous sparge recipe), but it is convenient.
No-Sparge
This method is the least efficient in terms of points per pound, but it’s easy and has the benefit of being immune to tannin extraction during the sparge. Like batch sparge, no-sparge is a draining rather than a rinsing method, and the beer is produced entirely from first runnings, resulting in a smoother, richer tasting wort at the expense of efficiency.
Rinsing vs. Draining
Commercial breweries practice continuous sparging because it is the most efficient way to rinse the grain of all the fermentable sugars. Extraction efficiency matters to commercial brewers because they are trying to get the most beer for the buck from their processes. Homebrewers generally have a different priority: we are trying to get the best beer for the buck. The difference in scale is in our favor. We can spend an extra dollar on malt to make up for a lack of efficiency, whereas a brewery would have to spend an extra 500 dollars and carry that cost thru to their bottom line. Continuous sparging is a rinsing process that depends on uniform flow thru the grain bed to achieve the best yield. The first runnings are rich in sugar, and as the sparge water moves thru the bed, this heavy wort is displaced by the less dense hot water, so the grain does not float as well. This causes the grain bed to compact, which can lead to a stuck sparge. You will also get a stuck sparge if the runoff rate is too fast; it will create a partial vacuum around the false bottom or manifold and compact the grain around it. The maximum recommended rate for continuous sparging is about 1 quart per minute. After the heavy first wort has been displaced, the remaining sugars in the grist particles will diffuse into the sparge water. This diffusion process takes time, and that is another reason to go slowly, otherwise the boil pot will simply fill with sparge water.The grain bed can be a few inches to a couple feet deep, but the optimum depth depends on the overall tun geometry and the total amount of grain being mashed. If the grain bed is very shallow, from lautering too little grain in too large a tun, then the filter bed will be inadequate, the wort won’t clear, and you will get hazy beer. A minimum useful depth is probably about 4 inches but a depth of about 8 inches is preferable. In general, deeper is better, but if it is too deep, then the grain bed is more easily compacted and may not let any wort through, making lautering nearly impossible. Since fluids always follow the path of least resistance, compaction can lead to preferential flow, in which some regions of grain are completely rinsed while others are not rinsed at all. Non-uniform flow is a major cause of poor extraction.But what if we didn’t have to rinse? If we simply drained the grain bed of the wort that was there, then all of our concerns about uniform flow and rinsing go out the window! This is basically what the no-sparge method consists of— you get a very rich wort with little effort. The problem is that quite a bit of wort is left behind. This is where batch sparging steps in—we mix another batch of water into the mash tun, let it sit 15 minutes to allow diffusion of the sugars to occur, and then drain this second wort to the brewpot. The second wort typically has a gravity of 1.016 or greater, so tannin extraction due to rising mash pH is usually prevented. (See Chapter 15 for more info.)
Figure 101—A well crushed grist with a good mix of large and small particles and unshredded husk.
Figure 102—Here is a picture of fine grind and coarse grind of the same malt sample according to the ASBC Methods of Analysis, Malt–4. Note that the fine grind has the consistency and particle size of cornmeal or flour. The barley husks have been ground up as well. The coarse grind sample below has much larger particles than the fine grind, but still smaller than the home grind picture in Figure 101. Also note that the husks in the coarse grind sample have been broken up and even shredded to some extent.
Figure 103—Typical 2 roller malt mill.
Table 24—Comparison of Particle Size Distribution (%) as a Function of Crush
Table 25—Comparison of Yield as a Function of Crush
Sparging Calculations
How do these different methods affect the beer recipe? Glad you asked, because it is a good way to illustrate the differences.
For example, here is a comparison of the standard 5 gallon recipe (continuous sparging) and the batch sparge and no-sparge recipes for a simple brown ale recipe:Grainbill Standard Batch No-spargepale ale malt 7 lbs. 7.6 lbs. 8.5 lbs.crystal 60 malt 1 lbs. 1.1 lbs. 1.25 lbs.chocolate malt 0.25 lbs 0.3 lbs. 0.5 lbs.Total weight 8.25 lbs 9.0 lbs. 10.25 lbs.Brewing Efficiency 80% 75% 65%Total mash volume 3.75 gal 4.9 gal. 8 gal.Each method produces the same 6 gallons of 1.041 wort using progressively more grain. The other difference is the size of the mash: 4.9 for batch sparge and 8 gallons for no-sparge, versus 3.75 gallons for the continuous sparge. The numbers above were calculated using “the long way” method described below.
Batch Sparge Calculations - The Short Way
The easy way to do the batch sparge and no-sparge calculations is to use the brewing efficiency percentages above to determine your grainbill and just see what you get. Many people do it that way and are very satisfied with the results. The method is the same as calculating malt extract quantities, except that the typical yield in ppg for batch sparging is 28 points/pound/gallon instead of 36 or 42 for liquid or dry malt extract. The 28 ppg comes from 75% efficiency x 37 ppg, based on the maximum percent extract for lager base malt. (Extract efficiency is explained fully in the next chapter.)
Example: To brew 5 gallons of a 1.049 OG beer:
1. 49 points x 5 gallons = 245 total points
2. 245 / 28 ppg = 8.75 pounds of grain. This estimate includes your specialty malts, which typically have a little lower yield. To obtain a more accurate grainbill, use this estimate as a starting point to figure out how much of each malt you would like to use in your grainbill and add up the contributions for each malt as described in the next chapter.
3. As you probably noticed, the grainbill for the batch sparge recipe cited above was 9 pounds, while here it’s only 8.75. The discrepancy is simply due to rounding up the individual malt weights in the “long way” example below. The difference between the continuous sparge and batch sparge grainbills is only a half pound of malt and you could simply add that difference solely as base malt, and keep the specialty malts at their original amounts, instead of trying to weigh up .533 pounds of crystal malt. The difference to the recipe character will be negligible.If you use a mash ratio of 2 quarts/lb (4.2 L/kg), you will easily get half your intended boiling volume from draining the first runnings. Typically you want to collect 1-1.5 gallons of wort more from your mash than the recipe volume to boil down to your intended OG.
Batch Sparge Calculations – The long way
Batch sparging works best when two sparge volumes of the same size are combined to create the wort. To keep the process simple, we want the first sparge volume to be what we get when we simply drain the mash. To do this, we need to calculate the batch sparge mash ratio that will give us that volume, including the water that will be absorbed by the grain. Then the batch sparge brewing process becomes as easy as conducting the mash, draining the first runnings to the boiling kettle, adding an equal volume of sparge water back to the mash, draining again, and boiling!First, let’s define the terms in the equations:Inputs:OG: Standard recipe original gravity (just the points part i.e. 1.049).Gr: Standard recipe grainbill (total pounds).Vr: Standard recipe batch size (e.g., 5 gallons).Vb: Standard recipe boil volume (e.g., 6 gallons).Calculation Coefficients:k: Water-retention coefficient (0.5 quart per pound)Outputs:W: Batch sparge water volume (quarts).Rb: Batch sparge mash ratio (quarts/lb.).S: Scale-up factor for grainbill.Gb: Batch sparge grainbill (total pounds).Vm: Volume of water for the mash (quarts).BG: Boil gravity (points).BG1: Gravity of the first runnings (points).BG2: Gravity of the second runnings (points).Vt: Total volume of the mash (quarts).1. Decide how many gallons of wort you will boil to achieve your recipe volume and thus your sparge volume (e.g. Vb = 6 gallons). W = Vb/2 (3 gallons i.e., 12 quarts)2. Calculate the batch sparge mash ratio. Rb = (Vb + (Vb^2 + 2k•Vb•Gr)^(1⁄2))/Gr (1.85 qts/lb.)3. Calculate the scale-up factor. S = 1/(1 – (k^2/Rb^2)) (1.08)4. Calculate the batch sparge grainbill. Gb = S•Gr (8.9 or ~9.0 lbs.)Grainbill Standard Batchpale ale malt 7 lbs. 7.6 lbs.crystal 60 malt 1 lbs. 1.1 lbs.chocolate malt .25 lbs. .3 lbs.Total weight 8.25 lbs 9.0 lbs.
5. Calculate the volume of water for the mash. Vm = Rb•Gb = W + k•Gb (16.6 quarts)6. Calculate the gravity of the first runnings. BG1 = 4•S•Vr•OG/Vm (1.064)7. Calculate the gravity of the second runnings. BG2 = 4•Vr•OG•(k/Rb)•(1 – (k/Rb))/(Gr•(Rb - k)) (1.017)8. Verify the combined boil gravity and recipe gravity. BG = (BG1 + BG2)/2 and OG = BG•Vb/Vr (1.040 and 1.049)9. Calculate the total batch sparge mash volume (quarts). The volume of 1 pound of dry grain, when mashed at 1 quart per pound, has a volume of 42 fluid ounces (1.3125 quarts or .328 gallons). Higher ratios only add the additional water volume. Vt = Gb• (Rb + .33xs) (19.5 qts. i.e., 4.9 gallons)
5. Calculate the volume of water for the mash. Vm = Rb•Gb = W + k•Gb (16.6 quarts)6. Calculate the gravity of the first runnings. BG1 = 4•S•Vr•OG/Vm (1.064)7. Calculate the gravity of the second runnings. BG2 = 4•Vr•OG•(k/Rb)•(1 – (k/Rb))/(Gr•(Rb - k)) (1.017)8. Verify the combined boil gravity and recipe gravity. BG = (BG1 + BG2)/2 and OG = BG•Vb/Vr (1.040 and 1.049)9. Calculate the total batch sparge mash volume (quarts). The volume of 1 pound of dry grain, when mashed at 1 quart per pound, has a volume of 42 fluid ounces (1.3125 quarts or .328 gallons). Higher ratios only add the additional water volume. Vt = Gb• (Rb + .33xs) (19.5 qts. i.e., 4.9 gallons)
No-Sparge Calculations – The short way
The easy way to do the no-sparge calculations is to use the brewing efficiency percentages above to determine your grainbill and just see what you get. Many people do it that way and are very satisfied with the results. The method is the same as calculating malt extract quantities, except that the typical yield in ppg for no-sparge is 24 points/pound/gallon instead of 36 or 42 for liquid or dry malt extract. The 24 ppg comes from 65% typical efficiency x 37 ppg, based on the maximum percent extract for lager base malt. (Extract efficiency is explained fully in the next chapter.)
Example: To brew 5 gallons of a 1.049 OG beer:1. 49 points x 5 gallons = 245 total points2. 245 / 24 ppg = 10.2 pounds of grain. This estimate includes your specialty malts, which typically have a little lower yield. To obtain a more accurate grainbill, use this estimate as a starting point to figure out how much of each malt you would like to use in your grainbill and add up the contributions for each malt as described in the next chapter.3. As you probably noticed, the grainbill for the no-sparge recipe cited above was 10.25 pounds, while here it’s only 10.2. The discrepancy is simply due to rounding up the individual malts. The difference here between the continuous sparge and no-sparge is two pounds, which is big enough that you will want to scale up your specialty malts too, and not just the base malt. In this case, you will want to add at least a quarter pound to each of the two specialty malts, and add the remainder to the base malt. Check the malt weight percentages to verify that your new recipe is still proportional to the original.4. When you batch sparge, you don’t want to add the full boil volume of water at mash-in because this will be too dilute for good mash chemistry and conversion. Instead, use a normal mash ratio of 1.5-2 quarts/lb. (3-4 L/kg), then add the remaining water after the mash is complete (an hour). Stir in the this additional water, let the grain bed settle, recirculate, and drain to your boiling pot. 5. To calculate how much water to add after the mash:The initial mash volume is 10.25 x R(2) = 20.5 quartsThe mash will retain about .5 quarts/lb. = 5 quartswhich leaves about 15 quarts of free wort. To collect 6 gallons (24 quarts) of wort total, you will need to add another 9 quarts of hot water to the mash.In the next chapter we will explore the concept of extraction efficiency more fully, and use it to plan all-grain recipes.