Hello and welcome back to the weekly Brewmaster-in-Training blog! This week’s blog will be dealing with one of the less explored topics in the brewing world- lautering. For folks who aren’t familiar with this term, lautering is the process of filtering wort (raw, unfermented beer) through a grain bed that has been created by barley husks and other solid matter after mashing. Lautering is the step during the brew day that comes just before transfering the wort over to the boil kettle. Lautering is also the time in the brew day when we sparge by adding more water onto the grain bed in order to wash any residual sugars out of the solid matter of the bed and into the boil kettle. I find myself oddly drawn to this step in the brewing process because of the intuitive nature of good lautering.
Lautering isn’t exactly a “1 +1 = 2” type of process. It is a process that deals with picking up on subtleties and keeping a watchful eye. Lautering is an art that crosses over several different disciplines. Good lautering starts all the way back in the milling of our grains and making sure that we leave enough barley husks intact for the lautering process. If we mill our grains too fine, we will end up with a flour-heavy consistency that will cause our lauter to become too “tight” and packed to allow water through. If we mill our grains too coarse, on the other hand, we won’t maximize the starchy extract that we need in order to have enough fermentable sugars available for our brewer’s yeast later down the line.
Spent Grains. Photo Cred: ironhillbrewery.com
Another thing we have to consider for a good lauter is the speed at which we run our pumps and fill our sparge water. As we recirculate our wort through the grain bed during lautering, our sugar-rich liquid should go from a turbid consistency to a more clear and bright consistency. What I like about this bit of the process is that it isn’t really a “set a timer and walk away” type of activity. It requires a caring, watchful eye to make adjustments and judge the exact perfect time to move to the next step in the process. This also requires balance. Circulate too fast and pressure will build in the bottom of the lauter tun due to suction, causing a stuck lauter. Circulate too slow, and you’re likely to be stuck at this step all day, wasting valuable time and resources in the brewery.
The final large factor in lautering is the sparge technique we choose to employ. Sparging is when we wash the grain bed to make sure that we have moved as many fermentable sugars as possible off of our spent grains and into the boil kettle. There are plenty of options when it comes to sparging technique, and it’s totally up to the brewer to determine which one is right for the brewery equipment. We can fly sparge, continuously adding a slow and steady stream of water on top of the grain bed while we drain the wort out of the bottom. We could also choose to batch sparge by adding lots of water at one time so that there is a level of water on top of the grain bed and then slowly drain wort out of the bottom. We can employ a hybrid of the two or really choose whatever program we think will fit our needs as brewers. And we must also know when to stop the sparge by taking periodic measurements of the sugar levels in the wort coming out of the bottom of the lauter tun. Once the sugar concentration in the wort becomes too low, we have to gauge when to cut it off so as not to over-dilute the wort in the boil kettle.
Wort layered on a grain bed in a clear tun. Photo Cred: “Aprender Para Beer”
So, we got into the weeds here a bit this week. But I would recommend playing with some of these parameters if you brew at home and want to look for ways to make better beer. Lautering is one the most customizable ways for a brewer to play around and try to get the most out of the raw materials. If we approach brewing as a discipline in which every large or small action we take has a far-reaching impact on the quality and taste of the beer (which is true!) then we can look at lautering as a bit of an unsung hero that allows us to tweak and improve our beer for those magical touches that make a drinker go, “Wow! I don’t know what it is, but this is some next level shit!”