Nick Carr on July 13, 2016 0 Comments You’re cranking along, a constant flow of golden, sweet smelling liquid swirling into the kettle. Things are good. You take a sip of the beer in your hand. Glance again at the flow and suddenly time seems to slow, a sinking sick feeling tightens your chest and stomach. The flow is slowing. You light the world with a few choice words about the stupidity of this hobby as you helplessly watch the golden stream become a seep. Night gathers. Boil time is an hour, then an hour and a half behind schedule. At two hours the last of your boil volume dribbles into your kettle. At some point, every all-grain brewer has found themselves in some version of the above tale. There are things you can do to try and fix a stuck sparge when it occurs, but there are also many things you can do to avoid this troublesome monster all together. Prevention almost always works better and is easier then response. Here are a few of my tips on how you can prevent a stuck sparge. 1. Lauter Tun Design There are many different lauter tun designs available on the market, add the myriad of homemade designs and you certainly have plenty of designs to choose from. But, there are a few design elements that should always be considered. Width: A wider lauter tun design allows for a shallower grain bed. This speeds filtering and helps prevent grain bed collapse (see the “Stay Shallow” section down below). Insulation: A lauter tun design that includes insulation, such as a cooler, makes it easier to maintain the right temperature, a key part of mashing and lautering (see the “Keeping Things Warm” section down below). The Filter: It is important to have the largest surface area possible covered by the filter. The best design is the false bottom. If it’s a homemade false bottom such as the bucket-in-bucket approach, it’s is important to make your holes about 1/8th inch in diameter. Any bigger and too much solid material makes it through, any smaller and you won’t get good flow. If using stainless steel braid or tubing with slits try to cover the broadest area possible in a uniform way. A poorly designed filter causing unequal filtration across the grain bed is a sure path to a stuck sparge. 2. The Right Crush No, I’m not talking about that middle school sweetheart who made you flutter with excitement, turned your legs to jelly and speech to some ancient lost language of monosyllables. This is about your malt. The grain should be crushed, not pulverized, and the husk left intact. The husk helps liquids filter through the bed. If both the grain and husk are crushed it will create a sticky, gummy mess and lautering will be difficult, if not completely impossible. But, on the other hand, if your malt is crushed to course you’re likely to get low extraction of sugars. It’s a fine line.. Don’t use a mill that crushes by a slicing or sheering action. In my opinion, a roller mill will give the best results. Play with the adjustment until you find the best setting and, for best results, you’ll have to readjust for different grain types. 3. Finding Aid If you’re brewing a batch that you feel may give you trouble — a lot of adjunct grains, wheat malt, or you suspect your malt is not crushed properly — then it would be wise to add a filter aid. Rice hulls, oat husks, and barley husks can replace the now absent malted barley husks. Rice hulls are the most popular and probably the easiest to get a hold of. Depending on the quantities of adjunct grains you’re using, add 1 to 2 pounds of hulls or husks per 5 gallon batch. 4. Time Out for Mash Out Once done with the mash, raise the temperature as quickly as you can to above 168°F. This is called a mash out. This temperature spike stops all further enzyme activity, sort of like turning off a light. It also keeps any residual starches and glucans from solidifying and making a gummy mess of your lauter. 5. Go Shallow This goes back to lauter tun design. The higher your grain is stacked the more pressure you have through the bed. At the same time you need a certain amount of grain to create an effective filter. Ideally, you need at least 4 inches, but don’t go much over 8 inches. If your current lauter tun doesn’t allow you do this or you’re trying to brew high gravity beers, then it may be time reassess your design and consider upgrading your equipment. Another solution would be to start brewing smaller batches. 6. Start Slow Lauter sounds a lot like loiter and you should take this to heart. Start your lauter slowly. At the beginning you’re trying to get the grain bed to “set up.” Too high a flow too early will likely create a vacuum below the grain bed. A vacuum compacts the bed, which basically creates a grain plug. 7. Keep It Warm You want to maintain properties created by the temperature increase of the mash out. If your mash temperature drops below 145°F the starches and glucans will began to solidify and gel increasing the likelihood of a stuck sparge. To prevent this keep your sparge water hot, ideally between 170°F and 180°F. And as mentioned earlier, lautering with an insulated system makes it easier to maintain the optimal temperature that go far in preventing a stuck sparge. 8. Stay Wet It is crucial that you keep your grain bed floating throughout the sparge to preserve its filtering properties. If the grain bed is not floating it collapses. Maintain an inch-layer of water above the grain bed. A sparge assembly can help you disperse and maintain the proper amount of water above the grain bed. 9. Pack Some Patience Even though you can increase your flow rate after you set up the bed don’t get in too much of a hurry. A five gallon batch sparge should take at least 20 minutes, and often times longer. Let it. Take your time. Sip on a beer. Clean up from your brew day. Take notes about the beer you brewed. Think about what you could’ve done better while you brewed. Brainstorm how you can improve your recipe. Contemplate the awesomeness of your latest creation. Whatever you do, just do something… Otherwise, you will get impatient with the process. 10. Vent The Vacuum Again, this is part of lauter design. If you have a lauter tun with a full false bottom filter plate you can run a hose between the false bottom and the top of the grain bed. How you get the hose below the filter screen is going to depend on your specific lauter tun design, but you’ll need one end of the hose under the plate. Plug or pinch off the end above the bed somehow. When and if you start to have a stuck sparge you can release the vacuum created under the filter by unplugging the hose and hopefully restarting flow. Takeaways Hopefully this bag of preventative tips and tricks will keep you from becoming the main character in our sad opening tale. Lautering is already considered the bottleneck in the brewing process. There’s no point in making the neck smaller than it already is. Use what you can from the above list. Set yourself up for sparging success, and if you have any other suggestions or tips that you think brewers can benefit from, please post them down in the comments below. Let’s help one another tame the monster. Cheers!
