The following is just my $0.02 on how to improve all grain consistency and efficiency with each and every recipe… or shall I say, just my $0.69!

Just when you think you have your system all tuned in, the beer gods decide to pull out their plyers and change the channel on you… or shall I say, they decide to channel your sparge, for all of you old enough to remember losing or breaking the frequency knob on your UHF/VHF tube TV.

This past weekend, I woke up and decided to brew a 5.25 gallon recipe that I’ve brewed a few times now. It’s a pretty standard 6.5% ABV single infusion West Coast IPA. With no wheat, rye or flaked adjunct in the recipe and a good looking crush, there was no reason to think things would go wrong. It was early and I didn’t feel like changing out of my pajamas, so I set-up my fly-sparge gravity system in the kitchen and started heating my strike water while I watched hockey highlights and consumed a pot of coffee.

By 10:00 am I was carrying 7 gallons of wort out to the garage and firing up my burner. As per my garage-brewing SOP’s (standard operating procedures), I removed a sample, cooled it, poured it into my test jar and dropped in a hydrometer to test the SG (starting gravity). Based on my calculations and average efficiency, I was expecting to see ~ 1.050 on the hydrometer, but instead, what did I see?… 1.032!!!

WHAT? How was that possible?

Much like calling tech support and having them ask if the device you’re calling about is plugged in to the wall and turned on, I decided to inspect the obvious. The crush! Was it crushed well enough or did some of the slightly smaller Maris Otter sneak past the rollers? Nope, everything was well-crushed! So that led me to the other obvious cause… the dreaded channeling!

What is channeling?

For those who haven’t experienced the joys of channeling, it’s simply the water deciding to take the path of least resistance during the lauter/sparge (separating the sugar from the grain) and omitting large areas of the grain bed. The result is less sugar making its way out of the mash tun and into the kettle. It happens without warning and you don’t notice until after the wort’s been collected. For this batch, I suspect the water started channeling during the last 2-3 gal of the sparge and unfortunately I was using a first wort hop addition, so extending the boil to reduce volume and meet the SG meant impacting the IBU’s. However, it was an IPA, so I extended the boil and sadly settled for 4 gallons… doh!

So how do you prevent channeling from happening?

A good crush, thorough dough-in, proper mash-out (a process used to raise the temperature to make the sugars less viscous for lautering/sparging) and maintaining an inch of water above the grain bed during a slow sparge is usually enough to reduce the chances, especially when there’s nothing unusual in the recipe. But despite implementing a consistent routine, channeling and stuck sparges still occur without warning.

So that got me thinking!

I’m always adding rice hulls to Wheat Beers and Rye IPA’s to prevent stuck sparges and have never had any issues, so why not add them to other styles to prevent channeling as well? Rice hulls contribute nothing in the way of flavour, colour or gravity and act solely as a filtering aid to keep the grain bed from sticking together, so theoretically they help to mitigate channeling as well. Rice hulls should allow sugars to be rinsed evenly and thoroughly across the entire grain bed and even eliminate the need to perform a mash-out.

If you’re averaging 80-84% extraction using the same recipe and toss in a ½ Lb of rice hulls, I’m willing to bet you extract at least 84% every single time, successfully increasing your efficiency and improving your consistency. You’ll spend less time worrying about potential sparge problems, can ditch the mash-out and forget about having to make adjustments after wort collection. As long as the crush is good and consistent, there’s no reason to suspect that rice hulls won’t improve extraction and consistency every time you brew and that’s a $0.69 investment I’m willing to make on every batch moving forward.

I’ll post my results at a later date after I’ve made the same beer a number of times, but in the meantime I appreciate any feedback or comments, especially from those already using them in recipes where they’re not normally required.