Section 5 – Appendices
Appendix E - Lauter Tun Design for Batch Sparging
On any given day, there is at least one guy standing in front of the brass fittings at the hardware store, trying to figure out what he needs to build his mash tun. Building a mash tun from a cooler or Esky is inexpensive and the easiest way to start all-grain brewing. You can use either a rectangular chest cooler or a cylindrical beverage cooler.
Choosing a Cooler
The original home lautering system was probably the bucket-in-a-bucket false bottom championed by Charlie Papazian in The Complete Joy of Homebrewing (Avon Books, 1984). This setup is fairly effective and very cheap to assemble. Using two food-grade 5-gallon buckets, the inner bucket is drilled with lots of small holes to form a false bottom that holds the grain and allows the liquid to run off; the sweet wort passes into the outer bucket and is drawn off through a hole in the side.
Picnic coolers (also called cool boxes or Eskies) offer a few advantages not available with buckets, adding both simplicity and efficiency. A cooler’s built-in insulation provides better mash temperature stability than a bucket can provide. Its size also allows mashing and lautering in the same vessel. Thus, all-grain brewing is as simple as pouring the grain into the cooler, adding hot water, waiting an hour, and then draining the sweet wort.
The shape of the cooler determines your grain bed depth. In general, deeper is better. If the grain bed is wide and shallow (less than 4 inches), it won’t filter efficiently, and your beer will be cloudy with debris. However, if the grain bed is too deep, it increases the risk of compaction and a stuck sparge from high flow rates. My advice is to pick your cooler based on your average batch. Don’t pick one larger than you really need and think that a larger one will give you more flexibility for future batches. If you pick one that is too large for the majority of your batches, your grain bed depth will be too shallow, and it won’t hold the heat as well. A 10-gallon cylindrical beverage cooler with either a false bottom or manifold works well for both 5- and 10-gallon batches The rectangular ice chest coolers also work well, and are commonly sized at 20, 24, 34, or 48 quarts (5 to 12 gallons), offering a good choice for any batch size. Many coolers have drain spigots that can be removed to make it easy to drain the wort via a bulkhead fitting. If you are using a cooler that does not have a drainage opening or spigot, lautering works just as well, if you come over the side with a vinyl hose, siphoning the wort out. You should use a stopcock or clamp to regulate the flow, and as long as you keep air bubbles out of the line, it will work great.
Everything you need to build a mash/lauter tun is readily available at a hardware store. The total investment for the cooler and all the parts to convert it into a mash/lauter tun is usually less than $50.
Picnic coolers (also called cool boxes or Eskies) offer a few advantages not available with buckets, adding both simplicity and efficiency. A cooler’s built-in insulation provides better mash temperature stability than a bucket can provide. Its size also allows mashing and lautering in the same vessel. Thus, all-grain brewing is as simple as pouring the grain into the cooler, adding hot water, waiting an hour, and then draining the sweet wort.
The shape of the cooler determines your grain bed depth. In general, deeper is better. If the grain bed is wide and shallow (less than 4 inches), it won’t filter efficiently, and your beer will be cloudy with debris. However, if the grain bed is too deep, it increases the risk of compaction and a stuck sparge from high flow rates. My advice is to pick your cooler based on your average batch. Don’t pick one larger than you really need and think that a larger one will give you more flexibility for future batches. If you pick one that is too large for the majority of your batches, your grain bed depth will be too shallow, and it won’t hold the heat as well. A 10-gallon cylindrical beverage cooler with either a false bottom or manifold works well for both 5- and 10-gallon batches The rectangular ice chest coolers also work well, and are commonly sized at 20, 24, 34, or 48 quarts (5 to 12 gallons), offering a good choice for any batch size. Many coolers have drain spigots that can be removed to make it easy to drain the wort via a bulkhead fitting. If you are using a cooler that does not have a drainage opening or spigot, lautering works just as well, if you come over the side with a vinyl hose, siphoning the wort out. You should use a stopcock or clamp to regulate the flow, and as long as you keep air bubbles out of the line, it will work great.
Everything you need to build a mash/lauter tun is readily available at a hardware store. The total investment for the cooler and all the parts to convert it into a mash/lauter tun is usually less than $50.
Rinsing vs. Draining – A Recap
Traditionally, homebrewers have sparged their mashes like the commercial brewers do: using water sprinklers or rotating sparge arms to rinse the mash uniformly for the best extraction. To get the most uniform flow through all parts of the grain bed, the mash must be kept fully hydrated with free water above the grist to help prevent settling and compaction. Lautering was typically an hourlong process of monitoring the flow rates and the runoff gravity to assure good extraction. I spent a year conducting fluid flow experiments with ground-up corncobs and food coloring, and enlisted the aid of two hydrologists and an astrophysicist, in order to gain a thorough understanding of how to optimize extraction of wort via continuous sparging. That work is collected in Appendix F.
Meanwhile, other homebrewers who were not so concerned with optimizing efficiency simply drained their mashes of the wort that was there using a slotted pipe manifold or stainless steel screen, dumped in another batch of water, drained again, and got on with their day. Frankly, I was disturbed by this flagrant disregard for technology: Sure it was easy and didn’t take as much time, but where was the fun in that?! Eventually, I realized that there was room for intellectual discussion and elegance of design in batch sparging, and I joined the bandwagon.
Draining the wort, rather than rinsing the grain bed, changes the design requirements. In the steady-state flow conditions of continuous sparging, you want the flow rate to be the same at every point in the grain bed, and a false bottom is the best solution for realizing this goal. The problem with this solution is that a uniformly high outflow rate can compact the grain bed uniformly into an impenetrable layer that results in a stuck sparge. High performance comes with a high-risk price tag. If you are simply draining the wort, you don’t care whether it is drained from over here or over there, as long as it drains. Extraction uniformity is achieved by stirring in the next batch of sparge water. The drainage points could be entirely along one side of the tun; it doesn’t matter, as long as you can drain it.
If the grain bed is drained from a single point with a high flow rate, the grain will quickly compact around that point, and flow will cease. The more you distribute that collection point, the lower the effective flow rate will be at any of those distributed points. This is the benefit of a slotted pipe or long screen—any decrease in flow at one point can be alleviated by an increase in flow at another point. Actually, false bottoms operate the same way, but the difference is that they are more uniform and symmetrical, so that a high flow rate at one point is a high flow rate everywhere. Slotted pipes are not good enough to have that problem. Thus, slotted pipes and screens work better for draining the wort than false bottoms at high flow rates. In fact, the standard operating procedure for batch spargers seems to be to open the valve all the way and drain the tun as fast as it will go! There is no benefit to draining the wort this fast other than less time. I think it is the same rationale as for driving a fast car fast—if you got it, you might as well use it.
Batch sparging works fine with false bottoms; you just need to be aware that if you attempt to go from 0 to 60 mph in two seconds, you run a greater risk of compacting the bed. Start slowly, and you won’t have any problems.
Meanwhile, other homebrewers who were not so concerned with optimizing efficiency simply drained their mashes of the wort that was there using a slotted pipe manifold or stainless steel screen, dumped in another batch of water, drained again, and got on with their day. Frankly, I was disturbed by this flagrant disregard for technology: Sure it was easy and didn’t take as much time, but where was the fun in that?! Eventually, I realized that there was room for intellectual discussion and elegance of design in batch sparging, and I joined the bandwagon.
Draining the wort, rather than rinsing the grain bed, changes the design requirements. In the steady-state flow conditions of continuous sparging, you want the flow rate to be the same at every point in the grain bed, and a false bottom is the best solution for realizing this goal. The problem with this solution is that a uniformly high outflow rate can compact the grain bed uniformly into an impenetrable layer that results in a stuck sparge. High performance comes with a high-risk price tag. If you are simply draining the wort, you don’t care whether it is drained from over here or over there, as long as it drains. Extraction uniformity is achieved by stirring in the next batch of sparge water. The drainage points could be entirely along one side of the tun; it doesn’t matter, as long as you can drain it.
If the grain bed is drained from a single point with a high flow rate, the grain will quickly compact around that point, and flow will cease. The more you distribute that collection point, the lower the effective flow rate will be at any of those distributed points. This is the benefit of a slotted pipe or long screen—any decrease in flow at one point can be alleviated by an increase in flow at another point. Actually, false bottoms operate the same way, but the difference is that they are more uniform and symmetrical, so that a high flow rate at one point is a high flow rate everywhere. Slotted pipes are not good enough to have that problem. Thus, slotted pipes and screens work better for draining the wort than false bottoms at high flow rates. In fact, the standard operating procedure for batch spargers seems to be to open the valve all the way and drain the tun as fast as it will go! There is no benefit to draining the wort this fast other than less time. I think it is the same rationale as for driving a fast car fast—if you got it, you might as well use it.
Batch sparging works fine with false bottoms; you just need to be aware that if you attempt to go from 0 to 60 mph in two seconds, you run a greater risk of compacting the bed. Start slowly, and you won’t have any problems.
False Bottom, Manifold, or Screen?
False Bottom
When you design your mash/lauter tun, you need to decide how you are going to collect the wort. Are you going to rinse (continuous sparging) or drain (batch sparging)? If you are going to use continuous sparging, you will need to consider the distribution and uniformity of flow through the tun (see Appendix F), and false bottoms generally work best for this. Batch sparging and no-sparge don’t require uniformity, and there are more options available. Here is a list of pros and cons for each:
Pros:● Prefabricated false bottoms for round beverage coolers are readily available from several suppliers and are easy to assemble. ● False bottoms are always more uniform when continuous sparging than manifolds—near 100%.
Cons:● False bottoms are tedious to fabricate yourself and difficult to fit to rectangular coolers. They should fit closely around the edges of the tun to prevent gaps that can allow sparge water to bypass the grain bed and reduce the yield. ● False bottoms are more prone to stuck sparges when the lauter flow is too fast, because they will compact the grain bed uniformly.
Pros:● Prefabricated false bottoms for round beverage coolers are readily available from several suppliers and are easy to assemble. ● False bottoms are always more uniform when continuous sparging than manifolds—near 100%.
Cons:● False bottoms are tedious to fabricate yourself and difficult to fit to rectangular coolers. They should fit closely around the edges of the tun to prevent gaps that can allow sparge water to bypass the grain bed and reduce the yield. ● False bottoms are more prone to stuck sparges when the lauter flow is too fast, because they will compact the grain bed uniformly.
Manifold
Pros:● Copper pipe manifolds are easy to build and fit to any size cooler.● Stuck sparges are rare with manifolds, because the grain bed will not compact uniformly.● Highly efficient configurations for continuous sparging are easily built.
Cons:● The efficiency of manifolds varies with the pipe spacing and the grain bed depth. ● The grain bed is not lautered below the manifold, so the pipe slots should face down and be as close to the bottom of the tun as possible.● Lots of slots to cut.
Cons:● The efficiency of manifolds varies with the pipe spacing and the grain bed depth. ● The grain bed is not lautered below the manifold, so the pipe slots should face down and be as close to the bottom of the tun as possible.● Lots of slots to cut.
Stainless Steel Screens and Braids
Pros:● No slots to cut.● Screens clear very quickly during the lautering recirculation step.● Stuck sparges are rare with screens and braids, because the grain bed will not compact uniformly.● Prefabricated screens and braid assemblies are available from several suppliers.
Cons:● Cutting the braid free from a rubber hose is a bit of work.● Half-inch diameter, light-gauge steel braids can collapse from the weight of the mash and make lautering difficult. One-inch hose braids won’t collapse.● Not well suited for continuous sparging.
Cons:● Cutting the braid free from a rubber hose is a bit of work.● Half-inch diameter, light-gauge steel braids can collapse from the weight of the mash and make lautering difficult. One-inch hose braids won’t collapse.● Not well suited for continuous sparging.
Siphon or Bulkhead Fitting?
You also have two options for getting the wort out of the tun: You can use a bulkhead fitting, or you can siphon out the wort. Many coolers have drain spigots that can be removed to make it easy to drain the wort via a bulkhead fitting. If your cooler does not have a drainage opening or spigot, you can buy a hole saw for your drill that will easily cut a nice hole in the cooler. Bulkhead fittings are available from several suppliers, or you can make your own. A bulkhead fitting is basically a short section of fully threaded pipe with two flat washers, two rubber washers, and two nuts for sealing around the hole that the pipe passes through. (See Figure 177.) A hose barb and vinyl tubing can be used to connect to the lautering device on the inside, and a ball valve and/or a hose barb is connected to the outside. Another suggested design using off-the-shelf fittings is detailed in Figure 180.
With the siphon method, vinyl tubing connects directly to the lautering device and just comes out over the side of the cooler. During the mash, the tubing can be coiled inside the tun with the lid on to help retain the heat. Both methods work well, although the bulkhead fitting looks spiffier and it is hard to siphon all the wort out. Whichever method you choose, you will also need a proper valve to regulate the flow rate. Ball valves are readily available in brass, chrome-plated brass, or stainless steel. Plastic stopcocks are an inexpensive option and work nicely in-line with the siphoning method.
With the siphon method, vinyl tubing connects directly to the lautering device and just comes out over the side of the cooler. During the mash, the tubing can be coiled inside the tun with the lid on to help retain the heat. Both methods work well, although the bulkhead fitting looks spiffier and it is hard to siphon all the wort out. Whichever method you choose, you will also need a proper valve to regulate the flow rate. Ball valves are readily available in brass, chrome-plated brass, or stainless steel. Plastic stopcocks are an inexpensive option and work nicely in-line with the siphoning method.
Brass Bulkhead with Ball Valve Design
Figure 180—Suggested design for brass bulkhead fitting1. ½” nylon barb to ¾” M hose fitting 5. ½” FIP to ⅜” FIP reducer2. ¾” F hose to ½” MIP adapter (brass) 6. ⅜” MIP nipple (1½”)3. Rubber O-ring (No. 15, ⅛” thick) 7. ⅜” ball valve (brass)4. Washer/spacer, trimmed to fit 8. ⅜” MIP to ⅜” barb
To assemble: 1. Slip the O-ring over the male threads on #2, so it rests against the flange.2. Apply some Teflon tape to the male threads of #2, and insert it through the spigot hole from the inside of the cooler.3. Slip the spacer over the threads, and hand tighten #5 to make a good seal.4. Assemble the rest of the parts in the sequence shown.
To assemble: 1. Slip the O-ring over the male threads on #2, so it rests against the flange.2. Apply some Teflon tape to the male threads of #2, and insert it through the spigot hole from the inside of the cooler.3. Slip the spacer over the threads, and hand tighten #5 to make a good seal.4. Assemble the rest of the parts in the sequence shown.
Building a Copper Manifold
A manifold can be made of either soft or rigid copper tubing. Choose a form to suit your cooler and design. In a round cooler, the best shape is a circle divided into quadrants, although an inscribed square works nearly as well. In a rectangular cooler, the best shape is rectangular with several legs to adequately cover the floor area.
Copper sweat fittings can be used to join the legs together. The fittings don’t need to be soldered; simply crimping the ends slightly with a pair of pliers will provide the friction to hold the assembly together. When you cut the half-inch copper water pipe lengths to fit the cooler, don’t forget to take the assembled elbow and T fitting lengths into account. Use a standard hacksaw blade to cut the slots—they don’t need to be any narrower. The slots in the pipes should only be cut halfway through and don’t need to be closer than a quarter-inch apart. Even a half-inch apart is fine. The slots should face down—wort that is physically below the slots will not defy gravity and flow upwards.
A wide variety of off-the-shelf brass fittings, such as hose barbs and compression fittings, can be used to connect the manifold to a siphon or bulkhead.
Copper sweat fittings can be used to join the legs together. The fittings don’t need to be soldered; simply crimping the ends slightly with a pair of pliers will provide the friction to hold the assembly together. When you cut the half-inch copper water pipe lengths to fit the cooler, don’t forget to take the assembled elbow and T fitting lengths into account. Use a standard hacksaw blade to cut the slots—they don’t need to be any narrower. The slots in the pipes should only be cut halfway through and don’t need to be closer than a quarter-inch apart. Even a half-inch apart is fine. The slots should face down—wort that is physically below the slots will not defy gravity and flow upwards.
A wide variety of off-the-shelf brass fittings, such as hose barbs and compression fittings, can be used to connect the manifold to a siphon or bulkhead.
Building a Stainless Steel Mesh Ring
The stainless steel braid from hot water hoses make good lautering screens. They are a bit of work to cut and disassemble, however, so here is one suggestion for making one.
Parts List:
24-inch x 1-inch diameter water heater connector⅝-inch compression T brass fitting (with included ferrules)2 1-inch lengths of ½-inch diameter copper tubing
Procedure:
1. Clamp one of the end fittings in a shop vise.2. Cut all the way through the metal sleeve that binds the hose braid to the end fittings with a hacksaw. This way, the ends are evenly trimmed and won’t fray.3. Pull the hose off the fitting in the vise.4. Clamp the other end, and repeat.5. Now, axially compress the braid to work it loose, and slide it off the hose. See Figure 190.6. Pull/compress the ends of the braid to make it narrow, and slide one of the copper tubing pieces onto each end of the braid. Let the end of the braid extend about one-eighth inch beyond the tubing.7. Slide a compression T nut over each end of the braid onto the copper pipe.See Figure 191.
Parts List:
24-inch x 1-inch diameter water heater connector⅝-inch compression T brass fitting (with included ferrules)2 1-inch lengths of ½-inch diameter copper tubing
Procedure:
1. Clamp one of the end fittings in a shop vise.2. Cut all the way through the metal sleeve that binds the hose braid to the end fittings with a hacksaw. This way, the ends are evenly trimmed and won’t fray.3. Pull the hose off the fitting in the vise.4. Clamp the other end, and repeat.5. Now, axially compress the braid to work it loose, and slide it off the hose. See Figure 190.6. Pull/compress the ends of the braid to make it narrow, and slide one of the copper tubing pieces onto each end of the braid. Let the end of the braid extend about one-eighth inch beyond the tubing.7. Slide a compression T nut over each end of the braid onto the copper pipe.See Figure 191.
Figure 191 – Assembling the mesh and fittings.
8. Insert a ferrule into each end of the braid. See Figure 191.
9. Slide the assembly snugly into the T, and tighten the nut so that it crimps down on the copper pipe.10. Do the same to the other side, and now you have a braided ring manifold that won’t come apart in the mash. This ring can now be connected to a bulkhead or siphon like the other systems.
A ring that divides the area equally in half (half the area is inside/outside ring) is nearly as effective as a false bottom for uniformity of sparge flow during continuous sparging. Flow uniformity doesn’t really matter for batch sparging, but it’s nice to have. See Appendix F for more information on uniform fluid flow during lautering.
9. Slide the assembly snugly into the T, and tighten the nut so that it crimps down on the copper pipe.10. Do the same to the other side, and now you have a braided ring manifold that won’t come apart in the mash. This ring can now be connected to a bulkhead or siphon like the other systems.
A ring that divides the area equally in half (half the area is inside/outside ring) is nearly as effective as a false bottom for uniformity of sparge flow during continuous sparging. Flow uniformity doesn’t really matter for batch sparging, but it’s nice to have. See Appendix F for more information on uniform fluid flow during lautering.
Estimating Grainbed Depth
In order to estimate the typical grain bed depth in a cooler, you need to know the dimensions of the cooler and the original gravity of your typical batch. And you need to know that 1 pound of dry grain has a mash volume of 42 fluid ounces, without freestanding water. (In metric units: 500 grams have a volume of 1.325 liters.)
Here is how you calculate it:1. Multiply your typical batch size (5 gallons) by your typical OG (1.050) and divide by your typical yield in ppg (30) to determine your average grain bill. 5 x 50 / 30 = 8.3 lbs.2. Multiply this weight by 42 fluid ounces per pound to determine the volume of the grain bed. 8.3 x 42 = 350 fl. oz.3. Multiply the grain bed volume by 1.8 to convert it to cubic inches. (231 cubic inches/gallon) 350 x 1.8 = 630 cu. in.4. Divide the grain bed volume in cubic inches by the floor area of the tun (9” x 14”) to get the resultant depth. 630 / (9 x 14) = 5 inches deep
If you want to calculate the total volume of the mash (including freestanding water), you just need to know that any water ratio beyond 1 quart per pound only adds its own volume.
For example, 8 pounds of grain at a ratio of 2 quarts per pound would equal 8 x (42 + 32) = 592 fluid ounces or 4.6 gallons.
Here is how you calculate it:1. Multiply your typical batch size (5 gallons) by your typical OG (1.050) and divide by your typical yield in ppg (30) to determine your average grain bill. 5 x 50 / 30 = 8.3 lbs.2. Multiply this weight by 42 fluid ounces per pound to determine the volume of the grain bed. 8.3 x 42 = 350 fl. oz.3. Multiply the grain bed volume by 1.8 to convert it to cubic inches. (231 cubic inches/gallon) 350 x 1.8 = 630 cu. in.4. Divide the grain bed volume in cubic inches by the floor area of the tun (9” x 14”) to get the resultant depth. 630 / (9 x 14) = 5 inches deep
If you want to calculate the total volume of the mash (including freestanding water), you just need to know that any water ratio beyond 1 quart per pound only adds its own volume.
For example, 8 pounds of grain at a ratio of 2 quarts per pound would equal 8 x (42 + 32) = 592 fluid ounces or 4.6 gallons.