Efficiency Rant

Efficiency Rant

Ever since we started fiddling with the mash tun and trying to make improvements to it, things have gotten worse. We tried fixing a leak in the ball valve by getting new ball valve that had a smaller connector piece that would hopefully fit more flush against the side of the mash tun wall. It did. But, I tightened everything too tight, and now the walls on the outside and inside of the mash tun are concave, which caused some more leaking. The next idea was to take a spigot out of an old cooler and try to put it into the new one. I tried to retrofit the regular spigot into our cooler and attach the ball valve on the output side and the stainless braid on the inside. It seemed to work and not leak when we tried it out before making the RIPA. However, we still had problems with the rye ipa and had bad efficiency numbers, but at least the cooler didn’t leak.

I am not so much concerned with the low efficiency number (we are back to about 65% instead of ~75%) but it is the inconsistency we are getting from batch to batch. Previously, we had been able to completely drain the wort from the mash tun and knew, within about two percentage points, what our efficiency was going to be. Lately though, we have left a lot of wort in the cooler because we cannot drain it out and our efficiency has suffered.

Efficiency can be broken up into several types. Conversion and lauter efficiency are what we are able to manipulate, while brewhouse efficiency (or efficiency into the fermentor) is mostly related to loss of wort due to hop/break absorption and the inability to completely transfer all of the wort from the kettle into the fermentation vessel. The efficiency into the fermentor is not very important to us, because it all depends on what happens after the boil and is usually constant.

Conversion efficiency happens during the mash. This is the ability to completely convert all of the sugars inside the grain into fermentable sugars that are dissolved in solution in the mash tun. Based on the amount of grain and the amount of water added, the first runnings should be at a specific gravity if you have 100% conversion. This is not our problem; the last 3 batches when we have been measuring conversion we have been averaging about 97% or better. Our loss in efficiency comes from bad lautering.

Lautering efficiency is the ability to lauter (or drain) all of the soluble sugars in solution from the mash tun into the boil kettle. Lots of things can have effects on the latuering efficiency like dead space. Dead space is a constant volume of wort that cannot be drained from a mash tun due to the way it is built. It is different for everyone based on their system. Basically, if the spigot to drain out the water is an inch above the bottom of the cooler, then when the water is below that spigot, no more is able to be run off, and the volume that is left is the dead space volume. This can be compensated for by making the tubes inside the cooler that drain the liquid touch the bottom, or by simply tilting the cooler at the end to make sure as much liquid is drained off as possible.

Another thing that can affect lauter efficiency is grain absorption. Grain absorbs both water (~1 quart of water per pound of grain) and sugar. The more grain that you have in a grist (10 lbs vs 20 lbs for high alcohol beers) the more water, and ultimately sugar, is absorbed by the grain. Because the preboil volume is always the same when doing a 60 minute boil (it will be larger if the boil time is longer), you have to use less water compared to grain in high alcohol beers to get out all of your sugar. As such, as the weight of the grain goes up, the efficiency will go down because you are leaving sugars behind. We are OK with this, we make a lot of high alcohol beers, and as such, the efficiency should go down so, but it should be consistent.

Lautering ability is different from deadspace, in the fact that lautering ability is the ability to drain as much wort as possible out of the mash tun. Lately, we have been leaving upwards of 1 gallon of wort in the mash tun (which is much much more than the dead space volume in our cooler) and this is where our problem lies. As of right now, now that the cooler isn’t leaking, am I out of ideas on how to increase this ability. I am hoping that the rye was the culprit last batch, and if so, this next batch should run a lot smoother. After 20 batches now, I know what to expect from out mash tun in the fact that I can calculate based on how much water goes onto the grain, about how much we should be able to drain out. If on this next batch, if I again miss those numbers and leave a decent amount of wort in the cooler, we are probably going to have to start from scratch again and buy a new cooler and build it from there. Hopefully, this does not happen, and our new mash tun will be working just fine.

Braukaiser.com is a website made by a homebrewer who explains all of this much better than I do, so you can go to his website if what I said sounds like French-Chinese. Sorry for the rant, but that has basically been what I have been researching and trying to fix for the last 2 weeks and why I haven’t been posting as much.