Where did I go wrong?

[jturman35]

Ok, so I attempted to brew 2.5 gals of Old Chub this weekend and came up about a gal short into the fermenter. I scaled this a recipe down using Beersmith. Probably not a good idea since this was my first AG.

Beersmith called for a mash in 2.8 gal. The problem is my kettle is 14" diameter and the false bottom sits off the bottom about 2". When I added 2.8 gals I could see this was not enough to accommodate 9lbs of grain so I added more water for a total of 4.5 gals. This was a big beer to begin with, but now do you think it will be View attachment IMG_6666.jpgView attachment IMG_6798.jpgdrinkable??

Here is what I had.
9.1lb grain bill
Mashed in 4.5 gal
Sparged with 1 gal
Preboil OG 1.052
1.5 gallons into the fermenter

 

[McKnuckle]

Trying to figure out how you lost so much volume... With 5.5 gallons of water and 9.1 lbs of grain, at a typical absorption rate of 0.12 gal/lb you should have produced about 4.4 gallons of wort in the kettle.

Boil for one hour, evaporate one gallon, and you’d be at 3.4 gallons ready to transfer to the FV. How did you lose nearly 2 additional gallons of wort?

 

[jturman35]

I'm starting to wonder if I obviously miscalculated my water volume when I mashed. I don't see how else my ending volume fell so short.

What's confusing is Beersmith said to mash with 2.8 gals. As wide as my pot is is the grain would be sticking up over the water level.

 

[McKnuckle]

Beersmith only knows what you tell it. It takes your entered losses into account when calculating the starting mash and sparge volumes. So if you don't accurately state those losses to match your system, the starting volumes would not be accurate. It also uses your stated mash thickness to calculate the mash volume. You don't have to follow it. You can mash with full volume - no sparge - or split the total water volume in half for mash/sparge. Or anything at all, really.

To end up with 2.5 gallons in the fermenter after a one hour boil, you'll need about 3.5 gallons in the kettle to start with (i.e. collected from mash/sparge). To get those 3.5 gallons, you'll need to account for roughly 0.12 gal/lb absorbed in the grain. So use your grain bill weight to figure that absorption loss out, and add it to the total water needed.

For example, with a 6 lb grain bill, you'll need to add 0.72 gallons on top of the 3.5 gallons to account for absorption. So now you're up to 4.22.

Pellet hops absorb roughly 0.09 gal/oz, so while that's a small amount, you should also include it for accuracy. Two ounces of hops would be 0.18, added to the above we now have 4.4 gallons total. You can split that in half for mash/sparge if you like - keeps it simple.

This example assumes that you fully drain your mash tun (no losses to dead space) and empty all of the kettle wort and break (minus hops) into your fermenter. If you can't manage those things, then factor in additional losses and add volume to the total to compensate.

 

[beermanpete]

Based on what you said your hot liquor volume seem ok. You need to add the volume of the dead space under the false bottom to the volume of hot liquor required based on the amount grain. After accounting for the water absorped in the grain you should have collected about 3.7 gallons of wort in the kettle. How much wort is left in your mash tun after you run out the wort?

You seem to have a low conversion and/or lauter efficiency. What was your mash temp? How long was you mash?

 

[bendog15]

It helps if you create a profile in beersmith under “my equipment”. You plug in all your size pots and the program will account for headspace, boiloff rate, and false bottom volume.

 

[jturman35]

Based on what you said your hot liquor volume seem ok. You need to add the volume of the dead space under the false bottom to the volume of hot liquor required based on the amount grain. After accounting for the water absorped in the grain you should have collected about 3.7 gallons of wort in the kettle. How much wort is left in your mash tun after you run out the wort?



You seem to have a low conversion and/or lauter efficiency. What was your mash temp? How long was you mash?

I collected every drop of wort. I mashed for an hour but the temp dropped to about 152-153

 

[jturman35]

I mashed for an hour between 152-153. Because it's cooler I had a hard time keeping temp at 155.

I did my equip profile in BS. I must have overlooked the false bottom volume. I will check. I will say this was my first brew using the false bottom. Last AG was BIAB and I tore bag on temp probe. I should have just bought another bag.

 

[McKnuckle]

In my opinion, there should never be more than a splash of wort left in the mash tun, regardless of whether you use a bag or a false bottom. The only wort lost to the mash should be that which is irretrievably absorbed in the grain. That amount can be as low as 0.08 gal/lb if you squeeze a bag, but 0.12 gal/lb is more typical and reliable as an estimate.

Therefore your only volume loss in the 9.1 lb mash would have been 0.12 gal/lb, or 1.09 gallons out of the 5.5 you mashed and sparged with. So you should have collected 4.41 gallons in the kettle.

Either you measured the mash and sparge volumes incorrectly, measured the kettle starting volume incorrectly, or left a lot of wort in the mash tun and didn't account for it.

 

[beermanpete]

I collected every drop of wort. I mashed for an hour but the temp dropped to about 152-153

Your mash temp and time are ok. I see from your other post you started at 155 degrees. A drop of two or three degrees is not a huge deal. How much wort did you collect in the boil kettle before you started the boil?

 

[SoCal-Doug]

In beersmith, edit your equipment profile. Upper right area in the Mash/Lauter Tun section (assuming the windows version) there is an entry field for "Mash Tun Addition". That is where you would put the amount of volume underneath your false bottom and other recoverable amounts. I also use that for the inch of fluid I keep on top of my grain bed during mashing/recirculation (but i'm on a 3 kettle herms system). You can mouse over any field and it will give you some tips on what goes in that field.

At 14" in diameter, 2" off the bottom, your recoverable fluid space is 307.88 cubic inches, thus 1.33 gallons.

Side note... If your pickup tube or whatever drain does not fully drain your kettle, that amount is not recoverable and should go into the field labeled "Lauter Tun Losses"

So... at 9.1# of grain, using the typical 1.25 qt/lb, you would need 2.84 gallons of water, PLUS the 1.33 gallons below the false bottom. Total needed would be 4.17 gallons. 1.09 gallons would be absorbed, leaving you 3.08 gallons. Add your 1 gallon of sparge and you would begin your boil with 4.08 gallons.

Going a little further, i'll venture a guess that you boil off about 1.75 gallons per hour with that size kettle (my 12" opening reliably boils off 1.6 gal/hr). With a 60 minute boil, you end up with roughly 2.33 gallons. This means you are a little short of your 2.5 gallon target. You will need too sparge 1.17 gal (or add the .17 as a top off pre-boil).

Having started with 4.5 gallons and a gallon of sparge, and ending up with 1.5, boggles my mind. Does your tun leave a lot of wort unrecoverable after draining? Could the grain possibly have held that much more (did not flow through the false bottom)? Extreme boil off rate somehow? Double check the height of the false bottom and the kettle diameter... but if you saw fluid on top of the grain bed during mashing.... Sure you didn't boil for a bit longer than 60 mins? how did you measure the 4.5 gallons and the sparge water? i'm stumped.

 

[McKnuckle]

And there is really no such thing as mash tun wort that is literally unrecoverable. If you can lift and tilt your mash tun, you can pour the loose volume through a sieve and recover it into the kettle.

At the end of the day, nobody else can estimate your losses. My 8 gallon 14" kettle boils about 0.9 gal/hr. That's a lot less than Doug's experience, which I'm sure is just as reliable for him as mine is for me.

 

[jturman35]

Yes lots of head scratching on my part. I actually did not even boil 45 mins. I got sick in the middle of the boil. I was already under the weather sinus/fever/literally laying in front of the toilet during the boil, so the whole day went to crap! This was my first attempt to brew using just a false bottom. Also first recipe using BS and also scaling down from 5gals to 2.5gals. Lots of learning on my part.

I have 1.5 gals in the fermenter. Is this going to be drinkable? Will it be a little on the stout side?

 

[jturman35]

I ended up at 1.026 and 15 bottles of beer out of 1.5 gal batch. If my math is correct I have 3.41% abv. If I was a 1.5 gal short going into the fermenter shouldn’t my abv be much higher? Man this batch is a mess!