17 replies to this topic

[OhioMurb]

Hmmm. I'm on my 11th all grain batch and I have fairly consistent efficiencies. BUT every so often, I get a really low number - here are my recent percentages:

[*]74[*]73[*]73[*]44[*]73[*]53[*]74[*]72[*]66[*]50[/list]My process is relatively the same (batch sparge, stir the same time, same water:grist ratio) and I buy my grain from the same LHBS that does the crush for me.Any explanation? The only thing I can think of is that my brew shop is fairly small and may not be turning over the grain quickly - am I just hitting stale grain on some of these low numbers? The style and OGs are different on all of them - would the type of grain that I'm using have that big of an impact?Really not sure what is going on here.

[tag]

Can you give us more information? What style were those beers? The o.g.?Do you check the milled grain - are they all milled similarly?Do you check the mash pH?

[RommelMagic]

Tag brings up some good points. I was thinking that the mill may have been adjusted, but most LHBS don't allow customers to fiddle with it. It could come down to whether or not your readings were off (such as a little too much quality control?) or if your temps were off due to an uncalibrated thermometer. And for those low readings, did you use the same water? Perhaps you used distilled?

[Malzig]

Have you checked the gravity of your first runnings against the thickness of your mash to determine if you have complete conversion? Not an iodine test, that only gives part of the answer.

[3rd party JKor]

I'd like to see the answers to tags questions, too. Including the styles and rough idea of the recipes for each batch.

[BrewerGeorge]

Stale grain wouldn't affect efficiency, it would just make stale-tasting beer.Like other have said, we need more information to diagnose properly. At a minimum 1) the style or color SRM, 2)what kind of water you used 3) target O.G. and lbs of grains mashed 4) target and actual mash temp. Ideally, it would be nice to get that info for each of your data points above. For the water one, you don't necessarily need to know the chemical specs of your water, just where you got it from.

[dmtaylor]

I find that efficiency is not a constant. It is very dependent on the original gravity that you are shooting for. When making a really big beer like 1.085 or more, it is very common for your efficiency to fall into the 50s. Conversely, when making a light beer around 1.040 or less, your efficiency might suddenly jump to around 90%!I track the sum of gravity points plus efficiency, which is not quite a constant, but is fairly close. So let's say on the average I am making beers around 1.060 with an efficiency of 70%. Then if I want to make a little bigger beer around 1.070, I know that my efficiency will fall somewhat, maybe down to about 60%, or maybe not quite so much -- maybe 62%? Something like that. And on the other hand, if I wanted to make a 1.050 beer, my efficiency will be closer to 80%. These are all rough examples.But first things first -- your efficiency will certainly vary wildly if you don't get exactly the same crush on your malts each and every time. If you grind your grist at the homebrew shop, who knows what you'll get -- your guess is as good as mine. But if you get your own mill, you can come up with the near-constant as I have suggested above. Like I say -- it's not exactly constant, but it gets you in the right ballpark.

[stellarbrew]

Do you double check that your LHBS is weighing out the grains correctly? If you only have 9.5 lbs of grain when you think you have 10 lbs of grain, your calculated efficiency will look unexpectedly low. If you are not already doing so, then weighing your grains yourself will remove one area of uncertainty.

[OhioMurb]

Would love the analysis, so here are the numbers...Munich Helles (OG = 1.046, SRM = 5.5, 10.2# of grain, target temp = 150, actual mash =- 154, eff = 74%)English Pale (OG = 1.054, SRM = 15.7, 12.7 # grain, target = 158, actual = 158, eff = 73.9%)English Brown (OG = 1.056, SRM = 18.7, 13# grain, target = 156, actual = 160, eff = 73.1%)Sweet Stout (OG = 1.082, SRM = 42.8, 21.75# grain, target = 152, actual = 156, eff = 44.3%)Helles Bock (OG = 1.077, SRM = 6.4, 17.5# grain, target = 154, actual = 160, eff = 73.3%)APA (OG = 1.058, SRM = 8.6, 15.5 # grain, target = 150, actual = 148, eff = 53.5%)Blackberry Stout (OG = 1.056, SRM = 37.2, 13# grain, target = 158, actual = 156, eff = 74.1%)Chai Amber (OG = 1.049, SRM = 22.8, 11 # grain, target = 152, actual 150, eff = 72.7%)Imperial Irish Red (OG = 1.066, SRM = 17, 16.25 # grain, target = 152, actual = 152, eff = 66.3%)Imperial Irish Red (OG = 1.073, SRM = 17.6, 18.5 # grain, target = 155, actual = 158, eff = 54.3%***Milling is all the same – LHBS mills behind the counter so nobody can muck it up or change the settings.I don’t check pH or conversion.Same tap water throughout.Also no new equipment - thermometer is the same, volume gauge is the same, etc.

[OhioMurb]

Okay - another thought...with the batch sparge, I try to get the first running volumes to match the second runnings (both about 3.5 gallons). But with the second runnings, I'll stop draining once I get to 6.5 gallons no matter how much is left in the tun. BUT, if I had drained all of the wort out (let's say to 8 gallons) then Beersmith would calculate my efficiency differently.So, for the beer I brewed this morning...OG into boiler was 1.060 and I stopped draining when the volume was 6.5 gallons. Beersmith tells me that the efficiency into boiler was 54.3%If I had let the tun drain entirely and had gotten 8 gallons of wort, then efficiency would be 68.2%I feel like I'm thinking about this the wrong way - what am I missing?

[ThroatwobblerMangrove]

Okay - another thought...with the batch sparge, I try to get the first running volumes to match the second runnings (both about 3.5 gallons). But with the second runnings, I'll stop draining once I get to 6.5 gallons no matter how much is left in the tun. BUT, if I had drained all of the wort out (let's say to 8 gallons) then Beersmith would calculate my efficiency differently.So, for the beer I brewed this morning...OG into boiler was 1.060 and I stopped draining when the volume was 6.5 gallons. Beersmith tells me that the efficiency into boiler was 54.3%If I had let the tun drain entirely and had gotten 8 gallons of wort, then efficiency would be 68.2%I feel like I'm thinking about this the wrong way - what am I missing?

How are you predicting the efficiency of hypothetically draining the tun when you aren't actually draining the tun?

[dmtaylor]

Yeah -- why are you putting in more water than you need if you know you only plan to drain 6.5 gallons? This will dilute your runnings. If you are trying to get half of 6.5 gallons -- which is 3.25 gallons -- out of both your first and second runnings, you need to work harder to make this happen. Either something in your software is goofed up, or you're just not putting enough effort into planning the water additions. What will happen if you add too much water and just drain to 6.5 gallons is that you're leaving a significant amount of sugars sitting in your mash tun. If you instead added just the right amount of water to get your second half of your volume (3.25 gallons) then you would get all the sugar you want, and your efficiency would be much more predictable.All that said, the results of my analysis of your ten batches above:Typically, your gravity points plus efficiency equals a pseudo-constant 128, plus or minus about 10 points, which is quite reasonable and predictable.However, with your Helles Bock, you actually did much better than anticipated, with gravity (77) plus efficiency (73) of 150. This greatly exceeds what would normally be expected, with a constant between about 128 to 138. So on this batch, you must have drained better than usual? Or else the crush of the grains was finer than normal? Otherwise, I'd have a hard time figuring out what you did differently here solely based on your data.Then with your APA, the opposite happened -- you used a lot of grain, but only ended up with gravity (58) plus efficiency (54) of 112, which is a great deal lower than I would have anticipated. Here, you might have used too much water and didn't drain well enough? Or your sparge wasn't working quite right that day so the water just drained past all the grains without soaking up much sugar? This would be called "channeling". These things are possible and should be taken into consideration.Other than that, all your other batches actually seem pretty normal to me. On your Sweet Stout, you got an OG + Eff score of 126, which is not far off of your average of 128. The efficiency does seem a bit low to me, though, as the lowest efficiency I have ever experienced (due to a bad sparge / no sparge situation) was about 53%. So maybe there was something odd going on here... but maybe not. And on the Imperial Irish Red, similar story, but this time you got an efficiency of, hey, 54%! And an OG + Eff score of 127, which is very much in line with what I would expect. Not bad for such a big monster of a beer.I'm hoping all this helps. You need to consider your goal when you formulate your recipe with some efficiency in mind. For bigger beers, you need to use more grain and knock your efficiency down (but never any lower than about 50%), and vice-versa for lighter beers. Your efficiency should NOT be a constant. But you do need to figure out how to do your water additions better so that you never ever leave a single drop of good wort sitting in your mash tun.

[OhioMurb]

It feels like this is volume-of-water related.I take an average absorption rate (after 11 batches, it's 13%) and then multiple that by the pounds of grain to predict how much water I need for first and then second runnings so I end up with 6.5 gallons. My calculations are not always on (I've seen some wild variations in absorption rate from batch to batch) but I try to be consistent. However, when I'm filling the kettle and am getting up past 7+ gallons I get nervous and probably don't drain as well (in a majority of cases, I drain until it runs empty, but maybe I'm not as consistent as I should be). It sounds like I should bite the bullet if my calculations are off, drain the same each time and then just boil it off to get it down. That makes sense - having too much wort isn't going to throw off my BU:GU ratio - low efficiencies are going to do that!I'm not convinced that draining the tun more consistently will solve this, but it's at least one more variable to remove.

[dmtaylor]

It's hard to tell from your response, but, are you accounting for water absorption in your grains for both the first and second runnings? This might be the reason you're ending up with too much sweet wort -- absorption only occurs with the first addition. After that, the grain is already saturated, so for the sparge, you just need to add 3.25 gallons and nothing more -- whatever you add for the sparge is what you'll get out, assuming you completely drained the first runnings.Just in case.

[3rd party JKor]

Yeah, like Dave said. You should be able to hit your volumes pretty accurately. If you drain off 3.2 gallons of first runnings and you're trying to hit 7 gallons, you should add 3.8 for the second batch. Everything you add the second time around should come through the bed.

[Steve Urquell]

I have very consistent efficiencies of ~ 72%. They will drop on bigger beers though.I can keep my eff. up if I dough in a couple degrees hot and stir the mash until the temps drop into range. Then stir every 15mins.I recently got lazy on a beer, doughed in and let it sit for the 1hr. mash w/o stirring= 60% eff.The next brew, with a bigger grain bill (of the same grains), I doughed in hot & stirred forever =72%

[OhioMurb]

Yeah - the sparge measurement is easy - no absorption, so everything runs through. I measure/heat the sparge water and then dump the whole thing in - no matter how much I'm pulling through in the first runnings - that's another point to tweak - I should measure it out and only add enough to finish to my 6.5 gallons.So, I've learned....

[*]Everything that goes in the tun has to come out into the kettle (drain, baby, drain)[*]Adjust my sparge volume based on how much wort I've gotten from the first runnings (think, gasp! on the fly)[/list]Anything else? The good news is that my beer has been great and any low efficiencies I overcome with adding some DME. It's just frustrating - sometimes I have that great brewing day where I hit all of my numbers and then I catch one where I'm 15% low. Note to self: RDWHH

[dmtaylor]

So, I've learned....

[*]Everything that goes in the tun has to come out into the kettle (drain, baby, drain)[*]Adjust my sparge volume based on how much wort I've gotten from the first runnings (think, gasp! on the fly)[/list]Anything else?

Yes, yes, and yes. If you are able, try to get the first and second runoff to be almost exactly the same volume. This will help to maximize your efficiency, which will consequently also make it a little easier to predict. But yeah, you've got the idea now.