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Home Brew Forums > Home Brewing Beer > All Grain & Partial Mash Brewing > Large dead space under false bottom
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Old 03-15-2011, 07:25 PM   #1
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Default Large dead space under false bottom

I bought a brewrite 10g pot with a false bottom. it takes over 2g of water just to bring the level above them false bottom. I've done a few AG batches with varying levels of success. I'm mashing in this pot right now. I do have another pot for sparge water. I do have an igloo, but I was was trying to do it all in one pot.

I'm just not sure how to factor that space in. If my recipe calls for 3g strike water then I need 5g in the kettle and then another 4+ to sparge.

Basically I'm starting with vary large amount into the boil kettle and a long boil.

I'm debating trying to modify the false bottom and use a dip tube.

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Old 03-15-2011, 09:08 PM   #2
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I'd put in some sort of tube, attached to the bottom of the false bottom to get down in there farther and get that liquid out. I recently moved from a cooler MLT to a converted sanke, and I relocated my dome-shaped false bottom from the cooler to the keg. There was a ton of deadspace under the thing because of the shape of the bottom of the keg, so I just screwed a 1/2" female threaded copper fitting onto the bottom of the falsie, and it gets almost everything out now.

It was a $2 fix and required no tools.

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Old 03-16-2011, 12:33 AM   #3
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I've often wondered about your question about the using 5 gallons instead of 3 for mashing in. In my setup i have about 1 gallon of liquid underneath my false bottom and i've never added extra, however a couple of times it felt like my mash was super thick, i would be curious to hear what works for you.

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Old 03-16-2011, 12:50 AM   #4
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Quote:
Originally Posted by martyphee View Post
I bought a brewrite 10g pot with a false bottom. it takes over 2g of water just to bring the level above them false bottom. I've done a few AG batches with varying levels of success. I'm mashing in this pot right now. I do have another pot for sparge water. I do have an igloo, but I was was trying to do it all in one pot.

I'm just not sure how to factor that space in. If my recipe calls for 3g strike water then I need 5g in the kettle and then another 4+ to sparge.

Basically I'm starting with vary large amount into the boil kettle and a long boil.

I'm debating trying to modify the false bottom and use a dip tube.
I have the same exact problem. I am fairly new to to this so you may not want to listen to me, but here is what I do:

First I know my total water for the mash and sparge say it 8 gallons. For simplicity sake say it works out to be 3 gallons for mash and 5 for sparge. With my 2 gallons underneath the false bottom that only leaves two gallons for actually in the grain which isn't enough, so I just bump up the mash 2 gallons.

So the mash for my equip is 4 gallons for mash and 4 gallons for sparge. But what I do is when I am draining the mash portion I aim to leave about 1.5 to 2 gallons in the pot, so I only collect 2 gallons. Then I add the sparge water. At that point there is about 6 gallons in the tun. It has been working for me very well. My efficiency has been between 80 to 89%. I also recirculate during the mash after about 30 min passes. I just open the spigot, drain about 2 gallons and pour it over the top of the grain, to get that water that sits below the grain actually into the grain.

I would also get a pick up tube as mentioned.

http://www.bargainfittings.com/index...&product_id=93
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Old 03-16-2011, 03:10 PM   #5
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That's the problem. The false bottom is almost 2" off the bottom and above the output port?

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Old 03-16-2011, 03:12 PM   #6
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Originally Posted by acslater55 View Post
I have the same exact problem. I am fairly new to to this so you may not want to listen to me, but here is what I do:

First I know my total water for the mash and sparge say it 8 gallons. For simplicity sake say it works out to be 3 gallons for mash and 5 for sparge. With my 2 gallons underneath the false bottom that only leaves two gallons for actually in the grain which isn't enough, so I just bump up the mash 2 gallons.

So the mash for my equip is 4 gallons for mash and 4 gallons for sparge. But what I do is when I am draining the mash portion I aim to leave about 1.5 to 2 gallons in the pot, so I only collect 2 gallons. Then I add the sparge water. At that point there is about 6 gallons in the tun. It has been working for me very well. My efficiency has been between 80 to 89%. I also recirculate during the mash after about 30 min passes. I just open the spigot, drain about 2 gallons and pour it over the top of the grain, to get that water that sits below the grain actually into the grain.

I would also get a pick up tube as mentioned.

http://www.bargainfittings.com/index...&product_id=93
Since my port is below the false bottom the pickup won't help unless I modify the false bottom. Right now it sits almost 2" off the bottom.

I think I'll give your method a try. Thank you for the input. It was one of my thoughts earlier, but wanted to find out how others were coping with this.
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Old 03-16-2011, 08:28 PM   #7
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Since my port is below the false bottom the pickup won't help unless I modify the false bottom. Right now it sits almost 2" off the bottom.

I think I'll give your method a try. Thank you for the input. It was one of my thoughts earlier, but wanted to find out how others were coping with this.
Wait...what? It sound like your setup is exactly like mine. The false bottom is above the port and the port is about 2" off the bottom. There are two problems it represents.

1. The is a lot of dead space under the FB that doesn't interact with the grain and throws off your mash water calculation. So we talked about that above.

2. With the port being high you will leave a lot of wort in the MT without something to get it out, so you will loose efficiency. I have measured my Megapot and it leaves about .75 gallons in the MT. That's a lot of wort. The link I gave you is a pick up tube to get as much of the wort out of the MT as you can. Now with my set up I get all but half a quart out. You should have plenty of room for a pick up under the false bottom.

Maybe you are thinking that the pick up goes vertical into the grain bed? It doesn't it faces downward to get all that nice wort you would otherwise leave.


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Old 03-17-2011, 02:50 PM   #8
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Originally Posted by acslater55 View Post
Wait...what? It sound like your setup is exactly like mine. The false bottom is above the port and the port is about 2" off the bottom. There are two problems it represents.

1. The is a lot of dead space under the FB that doesn't interact with the grain and throws off your mash water calculation. So we talked about that above.

2. With the port being high you will leave a lot of wort in the MT without something to get it out, so you will loose efficiency. I have measured my Megapot and it leaves about .75 gallons in the MT. That's a lot of wort. The link I gave you is a pick up tube to get as much of the wort out of the MT as you can. Now with my set up I get all but half a quart out. You should have plenty of room for a pick up under the false bottom.

Maybe you are thinking that the pick up goes vertical into the grain bed? It doesn't it faces downward to get all that nice wort you would otherwise leave.


ac
Yes, they do sound exactly alike. I wasn't thinking a pickup tube would be worth it. Though I might give it a try. I should be able to make one pretty easy like the one he's selling. If I had other things to order from him I would just order one, but I've already spent enough... :-)
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Old 03-17-2011, 03:03 PM   #9
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Check out this drawing... Did I get the current configuration correct? If so, then I would recommend the setup to the right.

I'm certainly not an expert, but here's my thoughts.

- That much dead space below the FB will certainly water down the wort prior to boiling since you can't get that wort out - I think - (not an issue if you lower your efficiency to increase your grains required to hit your OG).

- You are correct that you'd need to figure out how much dead space there is below the FB (which you've already done, ~2 gallons) and add that quantity to your strike volume.

Example:
10 pound grain bill
1.5 quarts/pound water to grist ratio
- you'd need 15 quarts of water (3.75 gallons) for your mash plus 2 gallons for dead space = 5.75 gallons in your MLT.
- you'd need to know the grain absorption (assuming ~.20 gal/pound absorption rate). 10 pounds x .20 gallons/pound = 2 gallons (someone check my math please).
- you'd then need your sparge water too (assuming 6 gal boil volume). 5.75 gal strike water - 2 gal (dead space loss) - 2 gal (grain absorption loss) = 1.75 gal + sparge water needed = 6 gal (boil volume). Solve for sparge water needed, 6 gal - 1.75 gal = 4.75 gal of sparge water.

SO... 3.75 gal strike water + 2 gal dead space + 4.75 gal strike water = ~10.5 gal of total water needed... (I didn't account for shrinkage (it's cold outside) and loss to trub).

Other considerations.
Do you make water adjustments? - You'll need to account for the larger volume of water...
Do you recirculate your mash water? - This could increase your efficiency a little bit but you've still lost the wort below the FB.

Bottom line. It would be muy bueno if you could get the FB lower and use a dip tube. If nothing else it would save some money over the long haul because your efficiency would go up a bit. The other advantage is that you can make slightly larger beers if you recoup that lost space. Other than that, there really isn't a disadvantage of your current design.

my $0.02

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Old 03-17-2011, 06:56 PM   #10
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Wow, exactly. Nice pictures. Visio? Lowering the FB would be good for larger batches. I just did a Dreadnaught and was at the pots limit with 17# (?). Had about <1" to spare.

The false bottom would be easy enough to lower. Just need to drill out some spot welds and add a hole/attachement for the dip tube. Just annoying having to modify an $85 FB.... How much space would be considered the minimum below the FB so as not to scorch the grain if I heat the pot?

Thank you for the suggestions!!

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