So I just upgraded from a Coleman cooler mash tun to a 15 gallon stainless with a false bottom that sits 2 inches above the bottom of my kettle. I filled my mash tun with water until the level reached to the top of the false bottom. I measured this volume to be just under 2.5 gallons. I then added the water back into the kettle and proceeded to drain the water through the valve. After the draining stopped I then measured the undrainable volume in the kettle to be 1 gallon. My question(s) is when I mash in I will not be able to stir the water below the false bottom. How do I calculate this volume back into my equipment profile? Since I can't stir this water do I add 2.5 gallons on top of my calculated strike water? Also since I can't stir the water below the false bottom will this water down my wort? Or do I subtract it out of my sparge water?
Stainless mash tun with false bottom calculations
- Thread starter rwing7486
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JLeuck64
Well-Known Member
I was thinking that you are wanting to figure out the dead space in your new mash tun, correct? That should just be the water left over after you drain it out. I think... that's what you are asking about? That dead space is the extra water we have to account for when figuring out how much water is needed to mash in with. One curious thing I've noticed with draining my mash tun is the siphon effect. If you just drain from a ball valve it will stop when gets to the level of the valve outlet. If you drain from a ball that has a drain hose connected to it the column of liquid in that hose (that is below the outlet of the ball valve) will continue to pull, or siphon, the liquid in the mash tun. Try it, might actually continue to pull more liquid out from the bottom of the tun than you would expect it too ( ;
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rwing7486
Well-Known Member
I will definitely do that as I plan to pick up a 3 to 4 foot high temp silicone tube to attach to my ball valve a day before brew day. But for now lets assume I have 1 gallon of undrain able liquid (my dead space). This volume I don't have any questions with, but I am concerned with the other 1.5 gallons that is trapped underneath the mash itself. This 1.5 gallon will not come in contact with the mash. So my question is how do I account for this during mashing?
My thought would be to put 2.5 gallons as my undrainable in beer smith - as this would give me the correct volume of strike water above the false bottom to achieve my desired mash thickness (most cases 1.25 qt/lb), BUT since beer smith does not know that only 1 gallon of what I listed is truly "Undrainable" I just subtract the 1.5 gallons that is useable out of my sparge water calculation as this will end up as my sparge anyway since I usually do 3 rounds of vorlauf at about 2 to 3 quarts per vorlauf before I let the wort run into the kettle. So all that water underneath the false bottom will be used as sparge during the vorlauf as this will be what comes out first before the wort does. Does this make sense?
RichH
Well-Known Member
I assume adding a dip tube to the valve would allow the kettle to drain most of that 1 gallon that is currently undrainable (sp?). Correct?
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rwing7486
Well-Known Member
There is a dip tube, but my kettle is more wide than tall which is why I am at a gallon - I will re run my un-useable volume test again once I get my high temp silicone tube. This number is not as important to me as it is easy to factor into strike and sparge calculations. My biggest concerns is with the useable volume underneath the false bottom as this will not be in contact with the mash water. I think my logic above makes sense as I when I first go to Vorlaf I will be pulling mostly water (very diluted wort) first as this is closest to the bottom. I just need to make sure I vorlaf at least 2.5 gallons total before I start my runnings into the kettle.
JLeuck64
Well-Known Member
I apologize in advance, but I just can't follow your logic on this one. I believe the dead space you are taking about will be in contact with the mash, through the screen in the false bottom.
audiophool
Well-Known Member
I am curious about this myself. My mash tun is similar to rwing's, with 2 gallons below the false bottom. I have been adding that amount to my strike water to arrive at my desired mash thickness. I.e., something like 1.25 quarts/lb + 2 gallons below the false bottom. However, my system is a HERMS and I recirculate during the mash, so the entire volume is available for enzymes to be diluted. Maybe my mashes are actually thinner than I have been thinking?
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rwing7486
Well-Known Member
It may be a little bit thinner , but shouldn't matter if it's thinnet or thicker, as long as the grains are always constantly saturated. I think the biggest thing is just making sure if you di add extra water to the mash is to subtract that amount put of the sparge so you don't exceed your previous boil volume. Efficiency might fluctuate a little depending on how you move the water amounts around but I think we are talking like 1 to 3% at most. The biggest factors significantly affecting efficiency is grain mill gap, deviating from your previous boil volume, and not having the correct boil off for your system.
I plan to brew two beers this weekend. I will update the thread with how I make out. I plan to run the process I described above.
Cheers
Rob
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rwing7486
Well-Known Member
I guess it's hard for me to explain on here but my concern with the water trapped under the false bottom is the fact that my mash paddle can't reach the water below the false bottom so I can't stir it to come in contact with the grain. So in reality the water above the false bottom is what is in doing the starch to sugar conversion as its in contact with the grain. In reality it doesn't matter if the water volume above is below the target mash thickness as long as 100% of the grain is saturated in water
JLeuck64
Well-Known Member
oh, ok I follow what you are saying then. I wouldn't be concerned at all because the whole container is closed. The density of the sugary wort is different at the bottom versus the top anyways. You will get conversion throughout the dead space also, I think the correct term used is osmosis.
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rwing7486
Well-Known Member
That is correct. But when you innitially go to vorlauf my assumption is you will start with avery low gravity wort as its mostly the water that was trapped underneath the false bottom. But as you continue to vorlauf the gravity will increase as the higher concentration of sugary wort will make its way to the bottom of the tun
I am pretty sure Jleuck64 is correct in that the wort at the bottom of the mashtun will not be watery. I would guess as sugars are created they will migrate toward the bottom under the the false bottom just like when you fly sparge. I know the wort at the bottom my cooler is higher gravity than the wort at the top when it has been sitting undisturbed.
Also I think as you stir the mash it would draw liquid up from under the false bottom anyway.
I am still using a cooler as a mashtun, but will be moving to a kettle and false bottom once I get brew stand built. Hopefully someone that understands how it really works will chime in.
Also I think as you stir the mash it would draw liquid up from under the false bottom anyway.
I am still using a cooler as a mashtun, but will be moving to a kettle and false bottom once I get brew stand built. Hopefully someone that understands how it really works will chime in.
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rwing7486
Well-Known Member
Well I will know this weekend. I will take a gravity reading of the first vorlauf I pull. Either way I process this brew I think I will be OK. I plan to batch sparge anways.
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rwing7486
Well-Known Member
Here is my planned brew study this weekend:
I am brewing two beers Saturday (for the NHBC) and plan to brew the first beer according to beer smiths calcs for a 1.25 mash thickness ( will only assume the 1.0 gallon undrainable). I will vorlauf 1 gallon of wort three times, taking a gravity ready each time. Depending on the efficiency I see from this brew process I will make the decision to either stay the same or change to a higher mash water volume for the second beer.
I would put in 2.5gal of dead space and select adjust Mash Vol for deadspace and manual remove the 1.5gals from the sparge volumes like you mentioned earlier.
I would also run through the numbers on paper or a spreadsheet to make sure they make sense. When I made a new cooler mashtun to do 10gal batches I kept getting too much run off from the beersmith batch sparge calculations. I did not double check the match and it took a few batches to get things zeroed in.
I would also run through the numbers on paper or a spreadsheet to make sure they make sense. When I made a new cooler mashtun to do 10gal batches I kept getting too much run off from the beersmith batch sparge calculations. I did not double check the match and it took a few batches to get things zeroed in.
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rwing7486
Well-Known Member
So this past weekend I was unable to conduct my experiment as I ran into some issues with the new mash tun. When I went to drain the tun after my single infusion mash I could not drain off any wort. Upon investigation my point of drain off was plugged due to grain getting past my false bottom. I am not sure if it was due to my crush being too fine that the husks were able to get through the false bottom? or maybe when I was stirring I bumped the false bottom creating just enough of a gap for the husks to get by the false bottom? Any ideas? my current mill gap is set to the thickness of a credit card ~0.35mm.
What is the gap between the bottom of your dip tube and the bottom of the kettle? A pic without the false bottom might be helpful.
After you measure the deadspace (undrainable volume) with the hose in place, I would calculate your "ambiguous volume" as:
You are correct that the ambiguous volume will affect your mash thickness, at least as far as stirring is concerned, and your mash kinetics should be more like a thicker mash (unless you add extra strike water.) I think you will be surprised that the SG in the ambiguous volume is higher than you expect, but it should be significantly lower than the SG in the bulk of the mash.
One way to reduce the effect of the ambiguous volume is to continuously recirculate your mash.
Brew on
After you measure the deadspace (undrainable volume) with the hose in place, I would calculate your "ambiguous volume" as:
Ambiguous_Volume = 2.5 gal - Deadspace
Put your deadspace in your BS equipment profile, and check "Adjust Mash Vol for Deadspace." Then when you actually go to brew, add your ambiguous volume to the BS calculated strike volume, and subtract it from your sparge volume. If you put 2.5 gal as your deadspace in the equipment profile, then BS will tell you to use too much total water.You are correct that the ambiguous volume will affect your mash thickness, at least as far as stirring is concerned, and your mash kinetics should be more like a thicker mash (unless you add extra strike water.) I think you will be surprised that the SG in the ambiguous volume is higher than you expect, but it should be significantly lower than the SG in the bulk of the mash.
One way to reduce the effect of the ambiguous volume is to continuously recirculate your mash.
Brew on
I wonder if putting some tubing around the edge of your FB to have it fit a bit more snugly would help. Also, could try other lautering methods underneath the FB (ie, jaybird has a few different levels of stands for FBs, or can use things like the braided hose, etc).
I think your logic of counting volume under FB as sparge after vorlaufing it in is fairly sound. 2.5gal is an awful lot under the FB, so you would definitely want to give that water another shot to collect as much sugar as possible, which short of recirculating, vorlauf is good. I don't know if there's a good way to "trick" Beersmith into this sort of calculation....I had issues with it figuring in volume under the FB (NOT deadspace) and ended up writing my own javascript for water calcs. I would think in Beersmith you might have to artificially thin your mash, then throw your boiloff way out of whack to allow you to still use the same amount of "sparge" water.
re: audiophool's recirc setup, from what I could see when I read around, people went anywhere from not counting any volume under FB, to volume under FB, to volume under FB + hoses + pump head in terms of "extra" water. I think as rwing mentioned, effectively being super-exact on this isn't too important. I count the volume under my FB. One thing to keep in mind - I would say the efficiency differences re: subtracting water from sparge volume would keep raising the bigger of a beer you're brewing, and one option of maintaining your normal efficiency is a longer boil. May not be ideal for all styles.
I think your logic of counting volume under FB as sparge after vorlaufing it in is fairly sound. 2.5gal is an awful lot under the FB, so you would definitely want to give that water another shot to collect as much sugar as possible, which short of recirculating, vorlauf is good. I don't know if there's a good way to "trick" Beersmith into this sort of calculation....I had issues with it figuring in volume under the FB (NOT deadspace) and ended up writing my own javascript for water calcs. I would think in Beersmith you might have to artificially thin your mash, then throw your boiloff way out of whack to allow you to still use the same amount of "sparge" water.
re: audiophool's recirc setup, from what I could see when I read around, people went anywhere from not counting any volume under FB, to volume under FB, to volume under FB + hoses + pump head in terms of "extra" water. I think as rwing mentioned, effectively being super-exact on this isn't too important. I count the volume under my FB. One thing to keep in mind - I would say the efficiency differences re: subtracting water from sparge volume would keep raising the bigger of a beer you're brewing, and one option of maintaining your normal efficiency is a longer boil. May not be ideal for all styles.
FuzzeWuzze
I Love DIY
Honestly I haven't heard of someone using a stainless mash tun like this unless they were recirculating with a pump and using either propane or electric to keep it at temps. When that's the case the lower 2.5 gals doesn't matter. How well is that thing holding temps with no external heat? I'd suspect you will have a hell of a time keeping it where you want it
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rwing7486
Well-Known Member
I have it on a propane burner. Holds heat pretty well - Only had to turn the burner on about 4 times to keep temp. I stirred the mash about every 5 to 10 minutes. I am wondering though if because of my grain crush and me stirring that I pushed some of the husks by the false bottom (gap between the false bottom outer edge and kettle inner edge). I am not quite sure but I could easily say about 15% of my grain husks were under the false bottom causing a stuck sparge. Any ideas on cause and fix?
Having used a false bottom and stainless mash tun before I converted a cooler, I'll chime in.
Check your gap on the grain mill. I've found this to be the most likely cause when I have problems.
Yes, you are probably getting some gain through the perimeter gap of the false bottom. You will always see some grain come through either this gap, or through the perforated stainless; it just happens. That being said, if that gap is sufficiently large, I'll second the earlier suggestion of adding a piece of split tubing around the false bottom, to act like an o-ring.
On your calculation of the 1.5 gallons under the false bottom that doesn't get directly stirred, but does get drained; I think this is irrelevant. You can mash thin or thick, and in my experience, it doesn't make a massive difference unless you are going to the extremes. Just look at BIAB techniques, huge H2O to grain ratios; legitimate method and I'd never be able to tell a traditionally vs. BIAB mashed beer.
Friendly reminder: If you do just add the extra volume of water, remember that this water adds to the heat mass of the tun, so your temperature drop will be lessened by the additional mass of hot water.
I always liked heating my strike water right in the mash tun. It was straightforward and with the kettle getting hot too, I would only need to reheat if I was mashing outside in the winter.
Check your gap on the grain mill. I've found this to be the most likely cause when I have problems.
Yes, you are probably getting some gain through the perimeter gap of the false bottom. You will always see some grain come through either this gap, or through the perforated stainless; it just happens. That being said, if that gap is sufficiently large, I'll second the earlier suggestion of adding a piece of split tubing around the false bottom, to act like an o-ring.
On your calculation of the 1.5 gallons under the false bottom that doesn't get directly stirred, but does get drained; I think this is irrelevant. You can mash thin or thick, and in my experience, it doesn't make a massive difference unless you are going to the extremes. Just look at BIAB techniques, huge H2O to grain ratios; legitimate method and I'd never be able to tell a traditionally vs. BIAB mashed beer.
Friendly reminder: If you do just add the extra volume of water, remember that this water adds to the heat mass of the tun, so your temperature drop will be lessened by the additional mass of hot water.
I always liked heating my strike water right in the mash tun. It was straightforward and with the kettle getting hot too, I would only need to reheat if I was mashing outside in the winter.
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rwing7486
Well-Known Member
Thanks CMAC! Ya I am no longer concerned with the water trapped under the false bottom but am more concerned with the grain husks getting by the edges of the false bottom and I appreciate your feedback. currently what gap do you have your mill set to? also do you use an "o ring" around your false bottom? below is a picture of tun with false bottom.
A credit card is ~0.030" thick, which seems to yield good efficiency and never run into stuck sparges, unless I'm making a wheat or lambic; but I use a metric ton of rice hulls to prevent issues with those beers.
I was using a keggle, so the false bottom came to rest just about the concave portion of the keg. Never had a need for an o-ring. When I've brewed with others using straight walled kettles like I see in yours, they don't use one either.
FuzzeWuzze
I Love DIY
Does you false bottom have a stand of some sort? To end up with that much grain down the side i cant help but wonder if you just hit the handle while stirring...even if it only jumped up a small amount for a second a ton of grain could get in there.
For example Jaybird False bottoms look something like this on the bottom to keep grain that may sneak down the sides from getting very far. When i take my false bottom off theres only a very small amount of husks and debris....not 15% of my grist!
If hitting the false bottom is the culprit, be more careful stirring! Or you could always think about using a pump of some sort to recirc for you so you cant bump the false bottom. That said if its just the false bottom design letting it by, a pump will be worse as all that grain getting by will clog the pump quickly.
For example Jaybird False bottoms look something like this on the bottom to keep grain that may sneak down the sides from getting very far. When i take my false bottom off theres only a very small amount of husks and debris....not 15% of my grist!
If hitting the false bottom is the culprit, be more careful stirring! Or you could always think about using a pump of some sort to recirc for you so you cant bump the false bottom. That said if its just the false bottom design letting it by, a pump will be worse as all that grain getting by will clog the pump quickly.
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rwing7486
Well-Known Member
Ya that's exactly how I set my roller gap as well except I use an old Soaring eagles player card since it doesn't have any raised numbers and lettering lol. Im guessing maybe it was a combo of my roller gap and me bumping the false bottom during stirring.
Does you false bottom have a stand of some sort? To end up with that much grain down the side i cant help but wonder if you just hit the handle while stirring...even if it only jumped up a small amount for a second a ton of grain could get in there.
For example Jaybird False bottoms look something like this on the bottom to keep grain that may sneak down the sides from getting very far. When i take my false bottom off theres only a very small amount of husks and debris....not 15% of my grist!
If hitting the false bottom is the culprit, be more careful stirring! Or you could always think about using a pump of some sort to recirc for you so you cant bump the false bottom. That said if its just the false bottom design letting it by, a pump will be worse as all that grain getting by will clog the pump quickly.
Ya it may very well be the reason as I did bump the single handle on top when stirring, but I didn't bump it that hard. I wish my false bottom had guards like the one you show. On the reverse side of mine there are 3 handles that are similar to the one on top
FuzzeWuzze
I Love DIY
I bet thats the cause then, with all the water in there swirling around it doesnt take much for those things to become bouyant for a short amount of time if they get hit. In the end it shouldnt really matter though if some grain gets under, as long as its not so much that it clogs your output valve.
augiedoggy
Well-Known Member
one of the advantages of recirculating is this all becomes a moot point really... I have 3 gallons under my false bottom myself.
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rwing7486
Well-Known Member
My output valve was clogged inside the kettle. It has a 90 degree elbow with a 3/8" hose barb that rests on the bottom of the kettle. I ended up scooping the wort and grain info my old Coleman cooler mash run and sparged from there
FuzzeWuzze
I Love DIY
Are you just stirring during the mash or are you stirring all the time because its on propane to keep it equalized?
Your fit doesnt seem wrong for your false bottom not that much should be getting by. My guess is the repeated stirring is getting grain under. In which case the solution is a pump, i'd look into a cheap P38-I pump. You can hook it up directly to your drain output via a nipple and use it to recirc back up and in.
For example this is the fit on my false bottom.
This will make your life WAY easier. I cant imagine having to stir my mash all the time and heat it up manually. Atleast you can get away from the stirring and only need to heat it up manually.
One downside if you decide to constant recirc is that you will lose heat faster.
Your fit doesnt seem wrong for your false bottom not that much should be getting by. My guess is the repeated stirring is getting grain under. In which case the solution is a pump, i'd look into a cheap P38-I pump. You can hook it up directly to your drain output via a nipple and use it to recirc back up and in.
For example this is the fit on my false bottom.
This will make your life WAY easier. I cant imagine having to stir my mash all the time and heat it up manually. Atleast you can get away from the stirring and only need to heat it up manually.
One downside if you decide to constant recirc is that you will lose heat faster.
@OP, Did you check the gravity of the first wort to leave the mashtun at the end of the mash, was it low or high?
