By Mike Retzlaff
Those of us who have been brewing for years tend to take many things for granted. The thoughts offered here are intended for the brewers among us with fewer miles on life’s odometer.
Mashing converts starch to sugars, degrades proteins and gums, and precipitates a number of other associated reactions. Unless you are strictly an extract brewer, at some point in the brewing process it becomes necessary to separate the spent grain from the sweet wort. The term for this is lautering. There are a number of ways to do it but virtually all systems work like either a tea bag or kitchen colander.
LAUTERING HARDWARE
False Bottom. This is probably the most often used piece of equipment for this particular brewing chore. Most often it is a disk with a multitude of holes drilled or punched through it. They are usually domed. Some false bottoms utilize nearly punched through disks which look like the knock-outs in electrical junction boxes. In commercial brewing, false bottoms are often made in pie-slice slotted sections which sit no more than an inch from the bottom of the mash or lauter vessel. Commercial units usually draw wort from several areas below the false bottom and convey the wort to or through a grant which is simply a pre-collection vessel. Some false bottoms feature laser or machine cut slots.
Charlie Papazian’s The Complete Joy of Homebrewing illustrates his Zap Pap lauter tun which consists of two nested plastic pails. You simply drill a “kajillion” holes in the bottom of the inner pail which nests in the outer pail. The outer pail has a hole drilled in the side near the bottom for a short section of plastic tubing which is fitted with a valve. I used such a contraption for years. It’s bare bones but works surprisingly well.
Manifold. These are generally constructed from PVC or copper tubing. Normally, slip fit joints are used to facilitate cleaning and the tubing is either drilled or slotted with a saw. They can be fitted to most any sort of vessel you would desire as a mash or lauter tun but are usually used with an ice chest.
Bazooka Tube. These wire mesh tubular screens come in a number of configurations. Some are a single closed end tube while others form a loop. Some form a tee shape. The run-off usually clears faster with these but they are a bit more prone to clog and cause a stuck lauter.
Mesh Bag. These bags come in an assortment of materials (usually nylon) and mesh sizes. This is the normal set up for the Brew in a Bag style of brewing. It works like a large tea bag and contains the grains during the entire mashing portion of the routine. The mesh bag can also used for steeping grains for extract and partial mash recipes.
The old English style of lautering relies entirely on simple drainage of the mash tun. This is the original no-sparge method. It is very inefficient but seems to be the quickest method.
SPARGING
Efficiency in lautering is assisted by sparging. The first documented sparging was done in Scotland. Sparging is simply rinsing the sugars from the mashed grains into whatever collection vessel is chosen. Most brewers lauter and sparge directly into the brew kettle. In general, the collection of wort begins with recirculation or vorlauf. The first few quarts of collected wort are gently added back to the top of the grain bed. The grain bed itself is the filter media. When the wort runs clear, the vorlauf is done.
Batch Sparge. The wort is steadily drained. Additional brewing liquor is prepared, heated, and added to the mash tun in one, two, or even three stages (dependent on the volume of the lauter tun). Each time additional sparge water is introduced, the mash should be stirred and another vorlauf performed before further collection.
Fly Sparging. In fly sparging, the grain bed is set with the vorlauf and additional heated brewing liquor is sprayed or trickled over the top of the grain bed. This can be in the form of a spinning lawn sprinkler shaped device, an inverted cone, or a deflection plate which keeps the sparge water from cutting a channel into the grain bed. Usually, the liquid level in the mash tun should be ½” to 1” over the grain bed during the sparge. This helps to negate channeling. Too much liquid over the top of the grain bed can cause the mashed grain to compact which can cause a stuck lauter.
LAUTERING PROBLEMS
Channeling. This occurs when the wort seeks the path of least resistance and cuts a channel toward the bottom of the mash tun. Much of the grain bed is bypassed by the sparge water. The wort in other areas of the mash tun doesn’t drain properly and far too much of the sugars in the grain bed are left behind. Lautering relies on the grain bed to filter out the non-liquid components in the mash tun. If that grain bed is compromised, you lose gravity points and efficiency. The usual cause is lautering at too fast a rate.
Stuck Lauter. This occurs when everything gets clogged up and the wort refuses to process through. There are two main reasons for a stuck lauter.
Lautering too fast. If the flow of the wort is excessive, it compacts the grain bed. How much time are you saving if you have to dig out the mash tun, layer the grain bed back in, and restart the lauter? Patience is a virtue! Too many brewers continually plot to hurry up the process. If you’re that pressed for time, go to the store and buy a six-pack.
Insufficient filtering media. The grain hulls are the normal filtering media in a mash. If you’re using a large amount of hull-less grain like wheat or debittered roasted grain, you may need to add hulls from rice or oats as a substitute. If the hulls of your malt are being shredded by the milling procedure, you may need to add rice or oat hulls. This addition is cheap insurance.
Another helpful tip is to preload the lauter tun with enough sparge water (brewing liquor) as to fill the void under the false bottom, in the manifold or bazooka tube. This keeps the mash liquid from rushing into that void when the mash is loaded into the lauter tun and causing the mashed grain to clog the screen, holes, or slots in the lautering hardware.
CONCLUSION
Brewing good beer on a consistent basis requires a knowledge of physics, chemistry, and to some observers, can appear to be alchemy. The lauter and sparge is just one facet of a typical brew day. Improve your skills and knowledge on each facet of brewing and maybe you’ll be as good a brewer as I hope to become one day.
Crescent City Brew Talk 