Sparging, also called lautering is a step at the end of the mashing process where hot water is run through the grain bed to extract a sweet liquid called wort. The wort is later boiled and fermented to produce beer.
The Sparging Process
After the mashing process is complete, the grains, water and sugar are still in suspension in the mash container, called the mash tun. The sugars are separated from the grains in a process called sparging. The mash tun typically has a false bottom or screen at the bottom with a spigot that allows the brewer to draw run-off from the bottom of the grain bed. Hot water at approximately 178 F is slowly added to the top of the grain bed, run through the bed, and drawn off the bottom through the false bottom and out the spigot to the boiling vessel. This extracts sugars from the grains and produces sweet liquid called wort for boiling. The initial runnings (first few quarts) drawn during the sparge process are recirculated back through the grain bed, as the early runnings often contain grain husks, crushed material and other undesirable elements. After the initial runnings, the grain bed will act as a filter and reduce the cloudiness of the runnings. Sparging is best done slowly so that a maximum amount of sugar can be extracted from the spent grains. The sparged wort is transferred to a boiler where hops is added and the mixture boiled before cooling for fermentation.
First things first, The Mash. Mashing is the process where starches are converted to sugars so that we may make good beer from them. There are infusion mashes, step mashes, and decoction mashes. Sparging does not change them. Sparging starts when the Mash is complete. So use volumes, ratios, etc. and so forth to Mash as you wish.
All sparges work on the basic principle of moving “stuff” (we are looking at sugars here) from places of higher concentration (the crushed malt) to places of lower concentration (the sparge water). How we manipulate this determines the sparge technique that we use.
The most common sparge method in commercial use today is the fly or continuous sparge. The properly performed continuous sparge is generally recognized as the most efficient sparge method in use today, that is a continuous sparge extracts the most (fermentable sugars) from the mash. A continuous sparge works by continuously introducing water (very low, or NO sugar concentration) at the top of the mash. This water then percolates down thru the mash bed increasing in sugar concentration as it goes. We can impact the efficiency of the sparge process by several means that we are familiar with, particle size of the crushed grain, grain depth, speed of draining, temperature of the process, pH, etc.
What are the advantages?
- Efficient extraction of the fermentable (and non-fermentable) sugars.
- Cost effective based on reducing the inputs (grain) into the process. (important for a commercial brewer, not important for a home brewer).
What are the disadvantages? Why doesn’t anyone ever talk about the disadvantages?
- When the gravity of the wort drops below 1.019 (some say 1.010) tannins from the husk are extracted. In the continuous sparge process the grain at the top of the grain bed, being continuously introduced to plain hot water, becomes depleted early in the process, thus the gravity at the top of the grain bed is meeting the requirements for extraction of tannins, hot, low gravity, and elevated pH. The pH increases (especially with base/light malts) as the pH buffering ability of the malt falls off with the extraction of the sugars (the SG of the wort drops). The gravity of 1.019 (1.010) is to ensure that the extraction of tannins has not occurred enough to significantly impact the flavor of the resulting beer. Please note that many excellent beers are produced using this method.
- Complex Procedure, must monitor to ensure the grain bed stays covered and the flow rate is appropriately slow for the efficiency produced.
- Requires special equipment, a false bottom or manifold designed to not allow channeling of the grain bed.
How To Fly Sparge Start by draining the cloudy wort slowly and returning it to the top of the lauter tun. When the wort runs clear, start collecting the wort slowly (2 cups every 90 seconds) while adding additional sparge water to the top of the grain bed. I let the wort level drop just to the top of the grain bed and then add sparge water to the top of the grain bed to maintain a level up to several inches above the grain bed. I do this with a “high tech” ½ gallon plastic pitcher dipping into my HLT and pouring into a colander on top of the grain bed to prevent the sparge water from drilling into the grain bed and causing channeling.
This is the simplest and least common of the sparging techniques. After mashing you simply drain the grain bed. Then add water (makeup) to the wort in your boil kettle to your boil volume. Advantages:
- The simplest of the sparging methods, just fill, mix, and drain.
- Does not require special equipment because channeling is not a concern. Any apparatus that will drain the liquid without allowing “chunks” is acceptable.
- Does not typically extract tannins
- Speed, it is a fast procedure potentially shortening your brewing day
- Makes a maltier beer, there is quite a bit of discussion on enhanced maltiness of the beers produced with this and the “batch sparge” method below. Here is a quote from George Fix ( http://hbd.org/hbd/archive/977.html#977-3 ) “I have found that to get a very high malt flavor the sparge must be omitted as well. This is an expensive way to brew since the amount of grains needed must be increased by a factor ~4/3. Nevertheless, some of the world's great ales and lagers have been brewed this way, and I have found it works in homebrewing as well for special beers. Clearly this is not the way to brew our standard beers.”
- Brewing efficiency is decreased as a good fraction of the potential fermentable sugars are not extracted. (See quote from George Fix above).
- Is not practical for big beers, requires a very significant increase in grain bill for high gravity brews.
- Not suited for a beer that should not have a malty profile.
OK, let’s offer a compromise solution between getting all the potential extract out (continuous sparge) and leaving a sizeable portion of the potential extract behind.
This is basically performing a No-Sparge twice recovering half of the kettle volume with each pass. Similar to No-Sparge above it goes like this: You have 10 lbs of crushed grain and you want a 1.3 qts/lb mash ratio (use what you need for your mash) you need 13 qts (3.25 gal) of mash water. The grain will absorb about .13 gal/lb so the grain will absorb 1.3 gal. This leaves 1.95 (3.25 – 1.3) gal, for a 7 gal kettle volume you need to add 1.55 gal to yield 3.5 gal (half of 7gal) for the first batch. You then mix all this so the entire volume is at the same potential gravity. Start by letting the lauter tun settle for a few minutes (10-15) then drain the cloudy wort slowly returning to the top of the lauter tun. When it runs clear start collecting wort slowly for a couple of minutes then open it up. For the second batch add half the desired kettle volume of 7 gal or 3.5 gal since the grain has absorbed all the liquid that it can and the grain bed is drained, then follow the same procedure. Again, unlike continuous sparging, flow has no impact on efficiency, only on how fast you finish.
- Not the simplest of the sparging methods, but a good compromise and a close second.
- Brad Smith: "much higher efficiency than no-sparge"
- "a homebrewer fly sparging might achieve 73% brewhouse efficiency while a batch sparger might only get 66% brewhouse efficiency."
- "stirring the mash upsets the grain bed, allowing more tannins and grain bits to make it into the wort. To reduce this risk, some brewers use a hybrid batch sparge method where they add sparge water slowly to the top and avoid stirring or completely draining the mash tun."
A Parti-Gyle is a modified Batch Sparge. Its purpose is to make multiple brews form the same wort, with each “batch” contributing fermentables to successively smaller beers. Making more than one beer from a mash. The principle is to
- Make a big mash, then
- Batch Sparge the first runnings to brew a strong or “stout” beer, Then
- Batch Sparge the second runnings to make an ordinary beer, Then
- Batch Sparge the third runnings, usually after freshening the Mash with some additional malt/grain.
Boil in a Bag Method
This method involves mashing the grains in a fine bag, sometimes made of nylon. Once the mash has completed, sparging can be done by lifting the bag and draining out the wort. The bag is lifted so that the bottom is still in contact with the level of the collected wort( to prevent oxidization of the wort). Sparge water at 65-68 degrees Celsius is then poured through the grains extracting a portion of the left over wort. A suitable sparge volume to use for a 23L ferment batch is 2L.
The efficiency of this sparging method is not as good as that of fly sparging, however the equipment required is not as complex and the efficiencies obtained usually end up in the range 70-80%.