First Mash Tun Batch

[JeremiLC]

Hello, I tried last weekend to brew my first batch of beer with a mash tun, since I've only did by BIAB, and it didn't work really well. So let's get down to it

First I builded myself a custom mash tun by modifying a 5 gallon cooler. I changed the spigot and added a bazooka screen.

With that, I had put 4 gallons of water with 14lb of grains, so my tun was really full (maybe that was my first mistake). After 1 hour, I started to drain the mash tun by opening the faucet and collecting the mash in a bucket. When they were enough mash in the bucket, I would take it with a measuring cup and put it back in the mash tun to recirculate the mash. The problem is that after 1h30, I only had 2 gallons of mash in my bucket and the mash not draining anymore. I guess I was supposed to have much more mash drained.

I'm trying to figure out what I did wrong. Is it because I had to much grains for my quantity of water? Also I read on some forums that for recirculating the mash, I need to use a hose connect from my spigot back to the tun, so is my technique for collecting the mash with a measuring cup and put it back in the tun wrong? and the reason why it wasn't draining good?

Thanks you in advance if you can help me.

 

[Wolfbayte]

Did you sparge (i.e., rinse)? Because you don't appear to have enough space in the MLT for a no-sparge mash on a 5 gal recipe, especially with that size grain bill, I suspect you should sparge with your setup.

Typical steps on a MLT with a batch sparge:
Mash
Vourlaf (recirculate a pitcher or three before draining)
Drain
Sparge
Vourlaf
Drain
Boil
Cool
Ferment

I'll bet if you sparge with 4 gals of water through the MLT (may have to split into 2 batches of sparge), you can get close to the pre-boil volume.

 

[JeremiLC]

Yes I did sparge to get to the volume needed to start the boil, but what was bothering me is that I was only able to drain 2 gallons before the sparge, and i'm suppose to have much more right? So I wonder if my method for recirculate the mash is the problem.

 

[Wolfbayte]

Yes I did sparge to get to the volume needed to start the boil, but what was bothering me is that I was only able to drain 2 gallons before the sparge, and i'm suppose to have much more right? So I wonder if my method for recirculate the mash is the problem.

It depends. You may have more wort lost between your grain and your drain (i.e., equipment loss) than you think. As you continue to hone your process you will learn your equipment profile, i.e., loss, trub loss, as well as factor in grain absorption. This will allow you to better dial in the exact amount of mash and sparge water to use to obtain your target wort amount.

Run your recipe through these sparge water calculators: http://www.brew365.com/mash_sparge_water_calculator.php or https://www.rackers.org/calcs.shtml. They, along with notes from your MLT batches will help you you learn your MLT equipment profile.

You are also correct that you had a hefty grain bill for that size MLT. I also wonder if you are used to squeezing the bag from your BIAB batches. That's harder to do in a MLT, especially if you sparge with hot, rather than room temp water.

 

[JeremiLC]

Ok, I will use the calculators next time. But you're saying that I used maybe too many grains for the MLT size, is that right? Also, I used to squeeze the bag with my BIAB batches, but I don't use one for my batch in a MLT, do I need to?

 

[mirthfuldragon]

Ok, I will use the calculators next time. But you're saying that I used maybe too many grains for the MLT size, is that right? Also, I used to squeeze the bag with my BIAB batches, but I don't use one for my batch in a MLT, do I need to?

Grain absorbs 1/2 quarter of water per pound of grain; 14 pounds would absorb 7 quarts (1.75g). You put in 4g of water with 14 pounds of grain, less 1.75g absorbed by the grain, leaving you with 2 gallons of first runnings. You lost another quart somewhere along the way. No surprise here.

I personally use a grain bag in my 10 gallon cooler so that I can squeeze the bag somewhat, which drops my grain absorption rate and increases my water yield (and boosts my efficiency a bit in my experience).

 

[JeremiLC]

Ok explain like that, it's logical. As for the bag, so you don't try to have a grain bed at the bottom of the MLT to filter you mash? at which step you squeeze it? after the draining or after the sparging? or both?

 

[mirthfuldragon]

The grain bag acts as a filter the same way (and better) than a grain bed would. I pull the bag and give it twist/squeeze every time I drain the mash tun. How aggressive one is with the squeeze/drain is a personal choice. Some people say not to squeeze too hard to avoid extracting tannins, and others have said it doesn't matter.

 

[BrewInspector]

Yes. You lost 1.75 or so gallons from grain absorption and another quart to equipment. Fairly normal. The next step was the sparge.

Use the calculators to tell you how much to mash with. Vorlauf and drain. Measure how much you collected and sparge with whatever remaining amount you need to get to your preboil volume (amount you intend to put in the fermenter plus the amount you boil off.) The amount you will sparge with should be similar if not identical to the sparge amount suggested by the calculator. This method prevents over sparging with too much water and getting to much preboil volume.

Your recirculation (or vorlauf) method had nothing to do with how much you ultimately drained.
I drain the mash into a pitcher over the kettle and return it to the tun shutting off the valve while pouring the pitcher into the tun. Repeating until it runs clear. 2-3 times.

 

[C-Rider]

BIAB works why change?

 

[beermanpete]

14 lbs of malt in a 5 gal. mash tun is too much. 12 lbs is the limit in my experience and does not provide any space to add hot water for a proper mash out.
What are your OG and volume (in the fermentor) targets?

 

[madscientist451]

I put my BIAB bag in a cooler but don't squeeze it, if the sparge get stuck you can pull up on the bag a little. I also manually recirculate with a 1/2 gallon pitcher, but I leave space in the tun to hot water to bring the mash temp up for circulating and sparge. I'll recirculate for about 5 minutes, then drain the tun and add the sparge water. I then put the first runnings on the stove and get the boil started while I'm sparging, this shaves a few minutes off the brew day. I'll let the batch sparge sit for a few minutes, then recirculate and drain and sometimes I'll get that boiling in a side pot in order to get the boil going faster.
Lets say you are doing a 5 gallon batch with 14 lbs grain.
You need 5 gallons of water for the finished beer, 2 gallons of water absorbed by the grain. 1.5 to 2 gallons evaporation loss when boiling and maybe another 1/2 gallon for trub or some other loss. So your total water needed is about 7.5 gallons.
A 5 gallon mash tun is a little small if you are making a big beer with 14 lbs of grain unless you want to use a somewhat low water/grain ratio.
So for big beers with that size cooler, I'd back off the total volume to 4 gallons or even 3.5 gallons, So for a 4 gallon batch you would just multiply your 5 gallon grain bill x .80.