So my buddy and I have about 4 all-grain batches under our belts. They've all been learning processes, so I'm thankful for that. One thing I've noticed though, is that our efficiency on this last IPA we brewed sucked. We were pretty disappointed when our starting gravity only hit 1.052 when we were aiming for 1.068-ish. For a 4 gallon batch, the calculators seem to say this is about 58% or so. (10.25 lb grain bill) Having said that, I've been doing some research on my own, and came to the conclusion we're having an efficiency issue. Here's a couple things I think are the culprit: - we don't know how to 'sparge' correctly. We've literally been heating up water to about 175-180, and pouring it into a bucket that we can then dump on top of the mash, stir, and let run out. We usually do this in 2 or 3 intervals (not pouring all the water on top at once). - We don't sparge long enough. Essentially, the above process takes us about 10-15 min. - We sparge with the valve fully open. - We're using the big rubbermaid gatorade cooler, but w/o a false bottom. I dunno how important that is, but it may be an issue. Anything else we should address? What are some ways to improve efficiency? Am I on the right track with blaming our weak sparge for this?
You are definitely on the right track. I'm too lazy to go pull #'s for ml/min flow rates etc, but if your doing your sparge like you described that is a huge drain (get it? haha) from your efficiency. What are you using for false bottom now? For a 4 gallon batch I would say, you should be taking at least 45 mins or longer to sparge. Your output should be at a weak stream. I usually have my valve only 25% open as opposed to having it 100% fully open. Look into continuous/fly sparging as well, this is basically running 160F - 168F sparge water into the top of the mash tun at the same rate as your weak stream output. Fly sparging will improve efficiency but you will need a 3rd vessel for this. If you do not have a 3rd vessel, you can do batch sparge. From "How to Brew": "Sparging is the rinsing of the grain bed to extract as much of the sugars from the grain as possible without extracting mouth-puckering tannins from the grain husks. Typically, 1.5 times as much water is used for sparging as for mashing (e.g., 8 lbs. malt at 2 qt./lb. = 4 gallon mash, so 6 gallons of sparge water). The temperature of the sparge water is important. The water should be no more than 170°F, as husk tannins become more soluble above this temperature, depending on wort pH. This could lead to astringency in the beer. The wort should be drained slowly to obtain the best extraction. Sparge time varies depending on the amount of grain and the lautering system, .5 - 2.5 hours. Sparging means "to sprinkle" and this explains why you may have seen or heard discussion of "sparge arms" or sprinklers over the grain bed for lautering. There is no reason to fool with such things. There are three main methods of sparging: English, batch and continuous. In the English method of sparging, the wort is completely drained from the grain bed before more water is added for a second mash and drained again. These worts are then combined. Alternatively, the first and second runnings are often used to make separate beers. The second running is lighter in gravity and was traditionally used for making a Small Beer, a lighter bodied, low alcohol beer suitable for high volume quaffing at mealtimes. Batch Sparging is a U.S. homebrewing practice where the full volume of sparge water is mixed into the mash. The grain bed is allowed to settle, and then the wort is drained off. The re-circulation step in this process takes place in the first minutes of the sparge. You can use more than one batch of water if you need to. This method differs from the English method in that the mash is not held for any significant time at the saccharification temperature before draining." Simply put, if your going to batch sparge you should (1) add heat in the form of x quarts of boiling water to get to a mash out temp to prevent a gummy stuck sparge, (2) recirculate first 0.75 - 1.0 gallon of wort or until semi clear and free of grain particulates, (3) drain 1st runnings completely at 25% flow rate, (4) add remaining volume of 160 F - 168 F water to mash, stir well, let sit 10 - 15 mins, and repeat steps 2 and 3. Hope this helps somewhat.
For a properly conducted batch sparge, the effect of flow rate on mash efficiency is negligible. The primary driver is the concentrations of sugars in the wort during each lauter step. That doesn't normally change within each step. Now if the mash was not mashed out (plus a slow lauter), or if a too fast drain contributes to a semi-stuck sparge (leaving pockets of wort behind in the grain bed), that would/could affect efficiency. But in the first case (no mash out), it's the longer effective mash time (continuing during the lauter) that affects efficiency (finishing conversion that was perhaps not finished before). In the second case, the pockets of wort left behind are something I 'd call a bad sparge.
A simple but important variable that seems to be often overlooked is how fine you mill your grain. Homebrew supply stores are notorious for milling grain poorly and this can have a big impact on efficiency. On my system I can go from 65% to 85% simply by changing how fine I mill my grain and nothing else.
OP: Is 58% your brew house efficiency (ie. a measure of the volume of wort and it's sugar content that you get into the fermenter post-boil) or your mash efficiency (ie. a measure of the volume of wort and it's sugar content that you get into the boil kettle pre-boil)? I ask because another factor (usually not as significant as grain crush though) to consider is are you sure you are getting proper volume measurements of either your preboil volume in the boil kettle (when calculating your mash extraction efficiency) or your postboil volume in your fermenters (when calculating your brew house efficiency. If not, it can skew your extraction calculations. Now if you are getting a 58% mash extraction, then you can focus on things like crush, mash ph, and lautering practices. If you are getting 58% brew house efficiency, then you can focus on all of those PLUS examine other data like evaporation rate, kettle dead space, transfer losses into the fermenter, etc.
We don't currently have a false bottom. We just use the cooler with the ss braided hose running to a ball valve for letting out the runoff. I was thinking of just doing this : (We also have another igloo cooler that we tried for our first mash tun, but it sucked because it let a lot of air out - we'd lose like 8-10 F over a 60 min mash. I suppose I could use this as a HLT, since it wouldn't really matter if we lost a couple degrees.) For the recirculation, I've just been doing 2-3 pyrexs worth before I start the sparge. Seems to be enough to get clear-ish wort - but I may not be doing enough there, either. We do get stuck sparges, but we're letting the wort out with the valve fully open, while one of us stirs the grain. We usually just pour the hot sparge water (174 F or so) on top, and then stir as it runs out into the boil kettle. I just recirculate 2 pyrexs full of wort before starting this process. I'm guessing we've been doing that pretty wrong. Hmm. Could be. The homebrew store we go to is a local guy that's big in the local brewing scene and does tons of brews himself at the shop. I mean, admittedly, I don't know exactly what to look for in perfectly milled grain, but I always thought it looked good enough (based on what I've looked up myself). I'll talk to him about the issue later this week and see what he says.
Oh, I didn't know the difference. Thanks... I calculated the volume and SG after the boil, wort chill, and transfer to fermenting bucket. We got the volume we were aiming for pretty dead on, just not the SG. Next time I'll check the mash efficiency too, preboil. Still learning. Thanks for all the help guys! Appreciate the insight.
