Electric mash tun question

[CreepsMcLane]

heres my set up:

20 Gallon Boil Kettle (220v ULWD element) 220v controller

15 Gallon Mash Tun (120v LWD element) 120v controller. bayou classic false bottom to raise my mash above the element. I also use a brew bag to keep little grain particles from getting scorched on my element. Mash is recirculated for the duration

10 Gallon HLT Cooler. I only like filling it up to 8 gallons because it has a slight leak out of the top port I have to fix.

BeerSmith and approximately 3 years of home brewing experience

I typically brew 10 gallon batches. I prefer the traditional three vessel method because I find it easier to calculate the entire process, there’s no surprises. I’ve done BIAB, didn’t prefer it. I tried a 2 vessel system, hated it. At one point I had a three vessel system and felt like I was brewing my best beers. I basically have that same set up right now but I brewed today for the first time back to that set up and majorly felt some woes.

Here’s my problem(s):

My beer I brewed today had an expected OG of 1.056 and I hit about 1.042 so I hit about 75% of my already calculated 75% efficiency. I had a major interruption while fly sparging courtesy of my two year old. I blame it on a very quick sparge but it left me wondering if there was a better way and also questioning my methods. My gosh this is turning into quite a story...

I went back into BeerSmith to play around with my equipment profile to see if that would put me where I actually was at 1.042 for an OG. Then I just get frustrated because I feel like my set up is unique and there’s no way to figure it out via an app. So, Beer smith said to start with 3.6 gallons for my mash. My false bottom comes up to the 3 gallon mark so I went with double the water and I cut in half the temp loss of Doughing in. worked out pretty well for brew day but then I start asking what’s my dead space of my mash tun? It 3 gallons space for mashing but yet I have full access to the 7 gallons so there is no dead space when thinking about volumes.

A faster way to ask this would be “do y’all use false bottoms with elements or do you just throw a bag in and because you’ve chosen a LWD element it just doesn’t scorch? Am I the only one with an element in their MT? HERMS is a not so distant goal, I’m just not there yet.

I can’t mash 10 gallon batches in my 10 gallon cooler I’m only comfortable filling up to 8 gallons.

I could just raise the temp by adding hotter water to mash out and such. But for multiple steps I’d rather just use my controller.

I feel very confident in my mash temp control. I feel less confident in my volume calculations which translates into my finished beer.

Did I leave any info out? I’m trying to be detailed. Sorry for the additional reading for possibly a very easy answer.

 

[processhead]

On occasions where I had lower than expected extraction efficiency, it was because of one of two unintentional mistakes I made during the runoff.
There can be other reasons for low efficiency, but I am betting this accounts for a fair number of cases among brewers.

1) The runoff took place at too rapid of a rate.
2) The runoff took place at too low of a temperature.


In my case, I was fly sparging.

 

[mredge73]

There are many studies that suggest that cold sparging is just as effective as hot sparging. I don't think your issue is temperature related.
It looks to be volume related. You want to maximize your sparge volume, aim for 1-1.25 qt per lb for your mash volume and reserve the rest for your sparge.


This is what my volumes typically look like for a 10 gallon batch. Batch sparging on my system yields a consistent 73-75% brewhouse efficiency using these constants.
There is room for improvement with these numbers; however they are consistent and that is what matters the most to me.

Brew
Grain Weight 18.00 lbs.
Boil time 1.00 hours
Batch size 10.00 gallons
Hop weight 3.00 oz.
Constants
Grain Absorption 0.14 gallons per lbs.
Water Evaporation 1.25 gallons per hour
Mash 0.32 gallons per lbs.
hop Absorption 0.15 gallons per oz.
Loss
Grain Absorption 2.43 gallons
Boil Evaporation 1.25 gallons
HLT Evaporation 0.50 gallons
Hop Absorption 0.45 gallons
Calculations
Mash Water 6.26 gallons
Rinse Water 8.37 gallons
First Running 3.83 gallons
Boil Volume 11.70 gallons
Total Water 14.63 gallons
Design For 10.45 gallons

 

[MagicMatt]

I can’t mash 10 gallon batches in my 10 gallon cooler I’m only comfortable filling up to 8 gallons.

Why not? Your MLT is 15 gallons, what does the capaity of your HLT have to do with your ability to brew 10 gallons? You should have plenty of room for sparge volume with 8 gallon HLT capacity, especially since you need so starting volume for your MLT.

I've never heard of anyone using an element in their MLT, but I'm sure someone has done so. My concern would be of scorching the wort - this is why if you want a direct heating element on the wort people generally use a RIMS system to minimize contact time with the element due to recirculation.

As for your volume woes, it seems like due to your very high false bottom, that you'll need to use more water than the standard 1.25 qt/lb ratio often cited. This will actually help with your extraction (see my comment to mredge73 below). So if you have 3 gal of dead space under the false bottom, that means you'll want enough water abouve the false bottom so that the grain is in contact 1.25qt/lb. Instead of simply doubling the suggested strike volume, you just need to add your deadspace. Thus, if you have say a 12lb grist, Beersmith will tell you to use 15qt strike volume (3.75 gal), so you'll actually want to use 6.75 gallons. This puts you at 2.25qt/lb, but you'll likely only realize this by recirculating the wort during the mash so that the volume beneath the false bottom interacts with the grain as well.

And since you're adding 3gal to your strike volume, you'll just need to deduct that from your sparge volume. If there really is no true dead space like you say (all of the liquid is reachable from your outlet), then the total volume of water needed for the brew is still the same, it's just that some of the sparge volume has been repurposed for mashing instead.

You want to maximize your sparge volume, aim for 1-1.25 qt per lb for your mash volume and reserve the rest for your sparge.

That's not necessarily true. In fact, the opposite is true: for higher extraction, you want the mash as thin as possible (higher water:grain ratio). 1.25 is often cited as the MINUMUM ratio, but the higher you go the better efficiency you'll realize, to an extent.