How to Sparge

All Grain Sparge

Sparging is the step in all grain brewing immediately following the mash, where the brewer uses hot water in a device known as a Lauter-Tun to rinse the newly converted sugars out of the grains. It is extremely important to note here that although it is the lauter tun where this process takes place, it is the grains themselves which do most of the work. More on this in a minute.

From the lauter tun, the sugary water (or sweet wort, as it is called) is collected in a vessel for later boiling. Although at first this may sound like a fairly trivial task, experienced brewers know that it can be the source of some of the biggest frustrations in making all grain beer. Just ask anyone who's had a stuck runoff, which can be caused by a number of factors, and results in no sweet wort flowing out the bottom of your lauter tun.

The Lauter Tun

The lauter tun is the vessel which aids the brewer in rinsing the sweet wort from the grains after mashing. Although there are a number of different types of lauter tun, they all function exactly the same way : sparge water is carefully poured in the top, and sweet wort is drawn off at the bottom. They all consist of a vessel to hold the mashed grains and some amount of sparge water. In the bottom of this vessel is one of a variety of devices which holds back the grains but allows the sweet wort to flow through to be drained from a spigot fitted in the bottom of the vessel. The 3 most common things found in the bottom of a lauter tun are (1) a false bottom with lots of holes in it, (2) a slotted copper manifold, or (3) an EZ-Masher or Bazooka style pipe and screen. In tests in Zymurgy magazine, all 3 of the above (as well as a couple of other styles of lauter tun) were found to perform almost identically. We used to use a home-made version of the EZ-Masher, made for us by our friend Jean-Pierre Boileau in Montreal, then made our own manifold, then bought a Phil's False Bottom, then made another slotted manifold. The moral of this story is that they all work extremely well. One type of lautering device may work better for me, while another type may work better for you. The only one I would not recommend is the "zapap". Just about everywhere you read, you'll see recommendations that the cheapest way to get yourself a lauter-tun is to use two buckets, one of which gets hundreds of little holes drilled in the bottom of it. Although this most certainly is cheap, I can speak from experience that it takes a good many hours of painstaking drilling to make one. After about 3 hours I finally gave up, and the thing was only about 2/3 finished. If you have lots of time on your hands and don't mind having a really sore arm for the next day or so, then go for it. Otherwise I'd strongly recommend something else.

Important Factors in Sparging

Conditions during the sparge have to be just right. Ideally, the sparge water should be about 168F (never going over 170F). Nearing the end of the sparge there is a danger of so-called 'oversparging', which can occur when the SG of the runoff drops below 1.010, or when the pH goes above 7.0. To help prevent this we adjust the pH of the final 1/3 of our sparge water to 5.5 to 6.0. Although many brewers don't bother checking the pH of their sparge water, it is advisable to invest in some good pH papers (ColorpHast, by Mercks), or an actual pH meter. Even if you don't happen to be in a position to make great adjustments to the pH, it is always good to have the values recorded for future reference. Not only are the temperature and pH very important, but so is the amount of time one takes during the sparge. Although there are newer sparging techniques which are done a lot more quickly (and extract a lower yield from the grain), a traditional sparge should take 60 to 90 minutes. This means that the brewer must carefully monitor both the flow of sparge water into the lauter-tun, as well as the flow of sweet wort coming out. One might at first think that adjusting both flow rates to be identical would allow the brewer to tend to other business during the time-consuming sparge (indeed, most do exactly this), however, some experienced brewers find they get higher extraction rates by constantly fluctuating the flow rates to work the grain bed like an accordion.

Aside from time, temperature and pH, the manner in which sparge water is added to the lauter tun is vital to the whole process. Care must be taken to gently distribute the sparge water so as not to have it disturb the grain bed - so simply dumping the water in is out of the question. Instead, some sort of sparge arm or other water distribution system is often employed to gently sprinkle the water into the lauter tun. Many people make their own out of copper tubing which they solder and drill themselves, while others might prefer to purchase a commercial product, while still others will adapt other regular household items to this purpose. For example, we used to use a stainless steel steamer insert that came with a set of pots we have. Although not quite as fool-proof as a proper sparge arm, it does a decent job of distributing the sparge water as long as the water is carefully poured through it. Nowadays we simply carefully pour the water directly into the lauter tun. Great care must be taken when doing this, however, so it's not recommended for beginners.

Once your sparge is completed and your grain bed has been drained, you'll be able to tell whether or not you did a proper job of distributing the sparge water. If the surface of the grain bed is relatively level and smooth, then you did a good job. If it's very uneven or has deep holes or pits, then you may have caused channeling, and may not have gotten as high an extraction as a result. Channeling is what happens when water does what it wants to do most - follow the path of least resistance. This will mean that some portions of the grain bed get more sparge water run through them than other portions. A poorly designed lautering device in the bottom of the tun can also be a cause of channeling.

Sparging Process

Depending upon the individual setup, sparging begins with the transfer of the entire mash volume to the lauter tun. Many brewers mash and sparge in the same vessel, so they won't have to worry about this step, but for those who don't, extreme care must be taken not to slosh the mash about during the transfer. As most experienced brewers know, aeration of the mash or wort while it is hot (hot-side aeration) can lead to off-flavors in the final beer. So the transfer should be done slowly and carefully, making certain to aerate as little as possible. Usually we mash and sparge in the same vessel, while from time to time we don't. When we do have to transfer, we simply use a 2 quart measuring cup or a saucepan to carefully transfer the mash.

Once the mash is in the lauter tun, a volume of wort must be circulated through the system in order to set the filter bed. As mentioned earlier, even though the process takes place in the mash tun, it is actually the grains themselves -- or more properly the grain husks -- which do most of the work during the sparge. This is why it is so vital to achieve a proper crush with a good mill. Only large, in-tact grain husks will be able to form a good filter bed during the sparge, and allow clear wort to run off for the boil. Recirculating wort through the lauter tun sets the filter bed and clarifies the worst of the protein and other gunk so it does not end up in the kettle. To do this, simply draw off a quart of wort from the out-flow spigot of the tun into an appropriately sized vessel, and carefully redistribute it into the top. This will normally have to be done 3 to 10 times before the wort starts to clear. It won't come completely bright at this point, but it will become noticeably clearer. Some home brewers use a food-grade pump at this stage to recirculate the wort.

After recirculation, the runoff begins. Fresh sparge water is added to the top of the lauter tun, while sweet wort is carefully drawn off the spigot at the bottom. While some home brewers keep it simple and maintain a large pot of hot water at the correct temperature on top of the stove, scooping out what they need in a large measuring cup for redistribution atop the lauter tun, others contain the entire volume of sparge water in a separate insulated vessel known as a hot liquor tank, which itself is fitted with a spigot, and a hose running directly to the sparge arm of the lauter tun. However complicated you decide to get, please remember that the runoff should take at least 60 minutes, and will probably take closer to 90. For the first few batches it wouldn't be advisable to try to work the grain bed, but after you become comfortable with the whole process you may want to experiment with fluctuating the outflow of the lauter tun to see if you can tweak out an extra percent or two of extraction.

Whatever the case may be, it is usually recommended that wort recirculation be done at a higher flow-rate. Then when it finally comes time to begin the runoff, one should begin at a very slow rate, and gradually increase the flow during the sparge. It will likely take 2 or 3 batches to get a feel for the proper flow rate as well as the proper increase, so in the meantime, just relax. As long as you take at least 60 minutes for your sparge, you'll do just fine. Let experience, not haste, guide you to the proper flow. If you want, do a couple of test-runs by filling your lauter-tun with water, and draining off the liquid to see how long it takes at various settings.

Alternate Sparging Techniques

In the late 1990s some alternate sparging techniques have gained a lot of popularity among home brewers. These alternate techniques usually require a lot less time, and also generally yield less extract from the grain when compared with a traditional sparge (known as fly sparging). Most folks say about 1/3 less. But proponents of these alternate techniques feel the sometimes dramatic savings in time is worth the bit more grain they have to use to brew their beers. Most commonly referred to as batch sparging, the basic technique is the exact opposite of the traditional fly sparge : you want to drain the lauter tun as quickly as possible. Just open up your spigot and let 'er fly! There are several variations on the technique with names that vary depending upon whom you ask. One common variant is that after the mash has converted the starches to sugars, you fill the mashtun up to the top with sparge water, give it all a good stir to mix it up, then recirculate and open up the spigot full tilt. Once you completely drain the tun, you fill it back up with fresh sparge water, stir, recirculate and drain it again. This probably originates from the British tradition of using the first runnings from the lauter tun to make a 'big' beer, and the second runnings to make a 'small' beer. Some proponents claim that not only is there a benefit in time savings, but the resulting beer is also maltier and at far less risk of being oversparged.