All-grain brewing: How to batch sparge
Sparging is sprinkling water over mash to rinse the fermentable sugars from the grain. The rinsing helps to extract about 70-80% of the fermentable sugars from the grain. These sugars eventually become your alcohol and beer. There are two common methods to sparge your grains: continuous sparge, and batch sparging.
Continuous (or Fly) sparging
Continuous (or Fly) sparging is the most popular, and this method is similar to how the big breweries sparge. Many homebrewers use this method as well. A sprinkler is positioned over the mash, and water is trickled over the grains to drain the sugars. The rate of liquid drained is equal to the amount of water added to the grain. This trickling of water “rinses” the grains and uses the grain bed as a filter to keep back any solids. Fly sparging usually requires some specialized equipment, but you can build your own system. Continuous sparging usually results in 70-80% efficiency if done correctly.
The problem with continuous sparging is that you can over sparge. pH is important for your mash, but with continuous sparging the pH can rise over 6.0. The higher pH will extract tannins from the grain husks and give your beer off flavors. Continuous sparging also requires more attention. You must monitor the temperature and the rate of water in and out of your mash. Stuck sparges can result if you are not careful.
Batch sparging is a method that was popularized by Denny Conn (he calls it the “Cheap ‘n’ Easy” batch sparge brewing ). This method is not really sparging, since batch sparging removes the sugars from the grain through diffusion. The grain is not “rinsed”.
When the mash is complete, the wort is drained completely. The grain is then sparged all at once with a second infusion of water. This is similar to how the English create “small beers”. The second runoff is a lower gravity wort since most of the sugars are collected in the first runoff. The small beer is the second runoff. In batch sparging, the second runoff is combined with the first runoff.
Batch sparging does not suffer the same problems as continuous sparging. The mash is “set and forget”. When the time has passed, you drain the wort and repeat the process. You do not need to monitor the pH because the wort does not get weaker (and higher in pH) over time. There can be a lower efficiency for batch sparging, but this is up for some debate. Many brewers have reported the same efficiencies as continuous sparging, but on average it might be slightly less. This reduced efficiency can be accounted for with a 5-10% higher grain bill or an extract addition to your wort. Adding extract at the end is probably the best method because you can hit your target gravity with more accuracy.
To batch sparge, you need a cooler converted into a mash tun. The cooler is “converted” to include a drain and a filter. The cooler is nothing more than your average beverage cooler. I use a Coleman Extreme cooler because it holds the temperature much longer. This is great if you want to mash overnight and split your brew time into two days.
Red vs. Blue
You might see comments on brewboards arguing between red and blue coolers. This is actually an inside joke, and the color of the cooler has no effect on the batch sparge method. Just find a good 40L cooler (for 5 gallon brews) that can hold a temperature for more than a few days.
The simplest method for creating a filter is to find a water supply line with a stainless steel braid at your local home supply store. The end of the water supply line is removed along with the inner plastic hose. The remaining stainless steel braid is used to construct your filter. (The actual steps and supply list for this conversion will be covered soon in another article.) There are also cooler conversion kits sold at your local homebrew supply store.
Batch sparging has the following steps: calculate your water, mash, infuse with water, drain, sparge with a second infusion, and drain. You can repeat batch sparging, but usually 2 is the magic number. Here are the steps in more detail.
1) Calculate your water additions
You need to calculate the water for your mash and each sparge. Typically you will only calculate water for your mash, one batch infusion for your first runoff, and one batch infusion for your second runoff. You can have more than one runoff, but two is usually sufficient. The total volume of all runoffs should equal your total pre-boil wort volume.
Your first runoff volume should equal half of your total pre-boil wort volume. If you intend to start your boil with 7.5 gallons of wort, your first runoff should be 3.75 gallons.
Total volume = First runoff + second runoff + …. First runoff = Total volume / 2
The first calculation is the amount of water to use in your mash. Your mash should be about 1.2 quarts per pound of grain. If you have 10 pounds of grain in your recipe, you will need 12 quarts (3 gallons) of water for your mash.
Mash volume = pounds of grain x 1.2 quarts of water
Grain will absorb some of this water. Typically grain will absorb 0.1 gallons for every pound of grain in the recipe. Again assuming that the recipe calls for 10 pounds of grain, you will lose 1 gallon of water due to absorption. We were using 3 gallons of water for the mash, and if we lose 1 gallon that will leave us with 2 gallons of water. (I’m so glad that I remember from college 3 – 1 = 2!)
Since we want the first runoff volume to be a total of 3.75 gallons, we will need to add 1.75 gallons of water at the end of the mash.
First runoff = (Total volume / 2) = Mash Volume + First Infusion - Absorption
The last batch sparge is easy to calculate if you are doing only one additional runoff. Our first runoff was 3.75 gallons, and the remainder of runoffs should also equal 3.75. Since we only have one additional infusion, our last calculation is 3.75 gallons.
2) Complete the mash with the first water addition
Heat the water calculated for your first runoff a bit higher than your target mash temperature. For example, if your target mash temperature is 150 F, heat the water to 165-170F. Add this water to your cooler, and then add the grain. Adding the water to a cooler filled with grain will create dry clumps and make it more difficult to mash all of your grain.
Once your mash is complete, add the first infusion of water. This additional water should be heated to 180-190F in order to get the grain bed temperature to 170F. The higher temperature is to help dissolve any remaining sugars.
Wait 10 minutes before progressing to the next step.
3) Drain the mash
Drain your wort from the cooler. The first few pints should be recirculated back into the cooler, until the runoff comes out clear. Recirculating the wort over the grain bed is also called vorlauf. Once the runoff is clear of grain particles, drain as much wort from the cooler as you can. While you are draining the first runoff, heat the second batch of water.
4) Add the second water addition
The second addition water should be almost boiling, so that you can get the temperature as close to 170F as possible. I usually try to get the water between 180-190F. Add this water to the emptied grain bed.
Wait 10 minutes before progressing to the next step.
5) Drain again
The instructions for this step are the same as step 3. Recirculate the first few pints until it is clear, and then drain as much as you can.
Why it works better
Batch sparging is superior to continuous sparging in the following ways:
1) Entrance fee is cheap. The equipment involved is a cooler modified with a filter.
2) No babysitting required. Since the water is added all at once, you do not need to worry about stuck sparges or pH imbalances. Just fill and drain.
3) Avoids channeling. When you continuous sparge the rinsing water can enter into channels, which will leave areas of your grain un-rinsed.
Hopefully you will find batch sparging an excellent introduction to all-grain brewing. The only “trick” to this method is accurately calculating the required water at each step. Other than that, this method is very low maintenance. Let us know if you have any questions in the comments. Happy brewing!
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I live in Denver, Colorado. This blog is everything about beer, wine, cider, mead and other spirits.
I am a avid homebrewer and winemaker. I’ve been making my own beer and wine for many years. I started making beer when I was in college (mostly because the drinking age in the United States is 21). My first few beers were horrible. The beers are much better now, and I often supply my neighborhood with free beer! It is a great hobby!