I will start by saying I have heard the jokes about a certain cooler color making better beer, that being said we have been using a 5 gal igloo for our mash tun and have no problems meeting our gravities, pre-boil and OG. This weekend we brewed a much larger recipe and required a larger tun so we converted a 12gal cooler to use. We mashed according to schedule and did everything the same as we had been doing previously. The results this time were off quite a bit and the pre-boil gravities fell well short. We wound up adding DME to make up the difference which was really no big deal but my question is this: Does the shape of the cooler make a difference in relationship to the amount of grain, in other words are there certain proportions that should be met to achieve a better efficiency. If the grain bed is too shallow will that make a difference compared to a deeper bed in the way the grain will mash? I know this might sound like a stupid question but I had to ask…BTW, the 5 gal. is yellow and the 12 gallon is blue…LOL!
Thanks (All water volumes were correct as well as the mash temperatures and the recipe amts were adjusted to correct for past efficiency measurements)
I have heard it mentioned that the bed being deeper than is is wide can cause problems but I think those are generally stuck sparges. I do know that efficiency on higher gravity batches tends to be lower. I don’t know why this is though.
I find the shape of my coleman extreme is really good for stirring the mash up and I have had problems with efficiency in the past due to not being able to stir well enough.
But major efficiency drops ussually have to do with poor crush of incorrect pH I think. Others will correct me.
Was this fly sparged, batch sparged, or no sparge? Or something else? How well does the bigger cooler drain compared to the other one?
+1 (I’d look into differences in lautering time/flow, sparge time/flow/volume, stirring, false bottom)
There is an ideal height to width ratio for mash tuns but relatively speaking you won’t experience differences within the homebrew world. I’ve brewed on a very wide 20 bbl tun, a square 7 bbl with equal height to width, and a tall 3 bbl tun; IIRC the 20 bbl system itself was radically inefficient but the other two were roughly the same. Are you sure you calc’d your water and grain needs correctly for the 12 gallon system? cheers, j
This is because the amount of wort lost to the grain bed is directly proportional to the amount of grain.
Assuming complete conversion of the starch in the grain bed, efficiency is then due to lauter efficiency. For a batch sparge, lauter efficiency is then dictated by volume lost to the grain bed and dead volume, as well as some technical details like stirring the sparge to evenly distribute the sugars in the sparge water.
Fly sparging is more dependent on tun shape and design, primarily because the tun needs to be designed to allow even flow through the grain bed. That means that the manifold needs to be designed correctly for the shape. A deeper grain bed will tend to be more efficient for fly sparging because more water will pass through each grain kernel on the way to the outlet, but be essentially irrelevant to batch sparging.
Another potential variable between two tuns is that one might maintain temperature better than the other. Loss of heat can decrease gelatinization and slow down conversion
Thanks for he replies! The rate of flow is the same and this beer was batch sparged as is all or beers. This cooler did lose heat and we thought we did a good job of monitoring and added did have to add 1.25 gallons to bring the heat back up at 40 minutes but we added another 15-20 minutes to the mash thinking we were making up for he loss?
It seems our temperature variables screwed us up a bit!?!
How much different were the efficiencies? It could be the temperature or it could just be the larger grist size (or another variable entirely, like crush from a different mill).
Our normal efficiency has been in the 75-80% range and this batch came in a paltry 63%. The grain came from our same supplier and crushed with the same, mill that was just calibrated. At this point I will go on the temperature issues as it’s getting colder in Chicago and there are quite a few temperature variables we have to play with now unless someone else has something a little more definitive to offer.
this implies the percentage and hence efficiency should be the same. to lower the efficiency it would be wort lost is proportional to the amount of grain raised to some power. which may be the case. (in other words amount of lost wort increases faster than the amount of grain increases.)
I’d use a symmetrical tun (cylinder or square over rectangle) for better balance in your beer. And I’ve found the optimal height/width ratio of the tun correlates to the OG/IBU, so use those short rectangular tuns for malty brews and the tall water cooler styles for IPAs.
And yes I’m yanking your chains.
Could you post your recipe and mash profile including volumes?
If you had to add 1.25 gallons of water to get your temp back up but you ran off the same amount of wort as you would otherwise then there was 1.25 gallons of lost wort left in the grain I would think. Don’t have the brain power this early in the morning to do the math but that might account for some efficiency loss (well gravity loss at any rate) don’t know if it’s enough to account for 12 percent though.
Including the questions from above, I have a few. What did you use as a manifold/false bottom? What were the mash temps?
Changing the brewery means you also need to get used to your new equipment. Was anything different in the build? IMHO, I think the temperature change is the culprit here.
I see where you’re coming from, but you’re making it more complicated than it is. Essentially, for a 10# batch you lose 1.2 gallons to the grain bed, or 16% to hit 6.5 gallon pre-boil. For a 20# batch, you lose 2.4 gallons, or 27%, to the grainbed. So, the amount lost increases faster than the total volume increases, but the amount lost is proportional the the grist weight.
Almost forgot to ask? What were the two grist weights?
recipe and procedure:
8.8lbs 2 row
1.6lbs Caramel 40L
14oz Munich
14oz Victory
9oz chocolate
Hops
1.25oz Northern Brewer-60min
1oz cascade-60 min
1oz cascade-0 min
1oz Saaz-0 mmin
Wyeast 1056
1 oz cascade dry hop 7 days
.5 oz saaz dry hop 7 days
Single infusion med. body batch sparge
Mash in 3.82 gallons at 168/step 156
Drain-sparge 2.07 gal, drain sparge 2.07 gal (15 minutes between)
Grain absorption at 1.42 and .25 dead space
6.25 gallons wort with 1.25 gallon boil off at 60 minutes
(Because we added hot water to raise temp during mash we actually got 6.75 gallons wort, experienced our first boil over but not terrible and still got our 5 gallons of wort)
Total grain bill was 12.2lbs which is why we needed to change tuns as the 5gal was not large enough with the required water to mash, last time we tried something this big the water oozed out when we put on the lid.
We used the same screen and valve for the cooler, no false bottom. Mash was stirred every 15 minutes and temp was checked at the same time, hence the adjustment. Hope all this info helps, I am still thinking the temp variables are to blame. :
Duboman, how much grain would be typical of a 75% batch?
Not that it couldn’t be the temp. You might want to cut down on the stirring to reduce heat loss, by the way.
On a slightly different note, how important is water chemistry to efficiency? Can it be a factor? I ask because last spring I started using all RO water and adding minerals back. I forgot to add the minerals to one batch last summer. My efficiency in that batch went from my normal of over 75% to the mid 60’s. Could be I’m overlooking something else, but the only significant variable I can think of is the water chemistry. Can the water profile affect efficiency?
Absolutely. It wil effect your ph which in turn directly effects conversion. Have you checked mash ph at all?
What was your mash pH?
Have you calibrated your hydrometer?
Some things to consider are the crush, mash pH, temperature, mash thickness (try thinning the mash a bit 1.5:1 or better) and increasing mash time. If the crush is on the coarse side then increase mash time until complete conversion has been achieved. Use a Refractometer to check the mash if you have one. Mash pH is also important (5.2-5.7). I use a pH meter but pH strips are okay. Mash thickness can be thined by adding more water to a thickness of 1.5:1 or better which will also help the conversion process. Also get your thermometer calibrated or buy a lab grade (NIST Traceable) thermometer to calibrate your working thermometers.
Mash conversion is a matter of time, temperature and proper mash pH.