You'd need a suitably sized 2nd vessel to dunk it into, then let it drip out over.
For a 12-14 pound grain bill you'd need more than a gallon of water, 2-3 gallons is more appropriate.
Efficiency, wort left behind, sparging (BIAB)
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You'd need a suitably sized 2nd vessel to dunk it into, then let it drip out over.
For a 12-14 pound grain bill you'd need more than a gallon of water, 2-3 gallons is more appropriate.
SlitheryDee
General Manager
What I plan to do is not exactly refined. I'm going to pull my grain bag out at the end of the mash, squeeze it, and then drop it into some preheated water to sit for about another 10 minutes. I'll probably stir it once when I put it in, then again just before I pull it out. Squeeze it again until I've got my original volume of sparge water back, and then combine the resulting water with the mash water.
I'm not really trying to optimize the process so much as try to do what I can to make my process repeatable should I or anyone else want to test under similar conditions. At some later point I'm going to do a full volume mash exactly double that size with the same grain bill so I have numbers that are directly comparable for the two approaches.
Morrey
Well-Known Member
The additional time it takes to sparge and squeeze a second time should not be a lengthy process. I am not sure I'd even heat the sparge water at least in the summer to try this next time.
What I plan to do by remaking the same recipe I made last week:
One gallon short on my mash strike volume. Sit a gallon of distilled water in the sun on my driveway while grinding/prepping/mashing. After mashing, hoist my grain basket and press as dry as possible. Unhook grain basket and sit down in spare 10G Igloo mash tun. Pour warm DI water over grain bed while agitating with paddle. Pull basket out of cooler and rehang over kettle while pressing again. Then add the 1G sparge water back into boil kettle.
With the exception of thinking into adjusting my chemistry, this should be fairly simple. If I got a 5 point boost in gravity doing this, I'll continue. If not, I don't think it would be worth it to me personally.
I don't want to derail the conversation, but I have a question. For reasons of space and simplicity I'm an extract brewer (I buy my kits online from various HB sites, usually whichever one is having the best sale at that moment). Every single instruction sheet I've seen always explicitly states words to the effect of, "Lift the bag of grains out of the boil kettle and allow to drain into pot. DO NOT squeeze the bag." And then I come here and everyone's talking about not "if" they should be squeezing their grains, but how hard and how many times!
So why do the kits always caution extract brewers to NOT squeeze the grains if there are no ill effects from doing so? Might my extract brews benefit from giving my grain bags a squeeze or two? Appreciate the advice!
So why do the kits always caution extract brewers to NOT squeeze the grains if there are no ill effects from doing so? Might my extract brews benefit from giving my grain bags a squeeze or two? Appreciate the advice!
SlitheryDee
General Manager
From what I can tell squeezing only applies to when you have a very strong, fine mesh bag, like most people BIAB in. If you squeeze your average muslin bag like the one most extract kits include for steeping grains, you run the risk of squeezing out grain particles or even bursting the bag. I don't think you really extract any tannins by squeezing, but you most certainly will by boiling the grain particles that fall out of the bag. You could probably get away with very gently and carefully squeezing though.
I believe with the steeping grains in an extract kit squeezing isn't necessary because the LME or DME will provide the necessary sugars.
Give it try, if you're bored next time. I think the amount of potential tannins on squeezing a bag of steeping grains would be minimal, but I may be wrong.
OP
OP
Excellent experiment!
It reveals what most of us squeeze critics have been expecting all along. Squeezing helps, but a decent sparge is 2nd to none. Physics can be proven.
Somehow I missed this the first time through, but my experience is that sparging an already-squeezed bag isn't effective.
When I poured in the two gallons of water to sparge, I stirred quite a bit, then took a sample. Gravity was 1.008, suggesting that sparging after squeezing wasn't going to yield much. But then I drained *and* squeezed, and the gravity shot up to 1.020.
So it depends on when and how people are doing it.
How about if I do a "poor man's sparge" by pouring a quart or two of heated water over the grain bag? Or, maybe I should start by transferring the grains from the muslin bag to the grain bag I already have (and already use for additional grains that I like to augment my recipes with) before I start the boil? Any thoughts there?
yes, you're right. i think about how much sugar are you pulling out of the grain, not the concentration of sugar in water. you can always boil down (or dilute) to the target gravity so my mind is always focusing on total sugars extracted.
in response to the posts about extra effort, for me its minimal. CA is still drought country, so i use ice bath and pump to my chiller for cooling. since i'll need the 2nd pot to hold the ice anyways, its not a big deal for me to have it handy when im mashing. i drain, squeeze, dunk sparge with hottest tap water, let it rest with a few stirs while kettle gets towards boiling, then drain and squeeze again.
if i want more sugars in kettle, i dump it in kettle. if i dont need it, i boil it down for starter wort.
im toying with the idea of doing this as standard procedure now. using less ice, letting ferm chamber bring the wort down to pitch temp overnight, and having fresh yeast in a starter liquid made from identical grain bill.
OP
OP
At least a couple gallons.
When I did my "experiment," I first tried a gallon sparge in a 12# grain bill; it left a sort of oatmeal consistency. The second gallon made it more like the consistency of a traditional mash.
rancocas
Active Member
I recently made three changes to my BIAB process.
1. Got a huge pot 15 gal, so full volume mash. I do about an hour of draining from a pulley and some squeezing. No more sparging.
2. Started milling my grain. 0.025" vs store milled.
3. Bought a small recirculating pump which I start up while heating up the strike water and continue during entire mash.
What used to 1.050 OG is now 1.065 with the same grain bill. I could not believe my hydrometer reading the first time. But I have repeated this five times now.
1. Got a huge pot 15 gal, so full volume mash. I do about an hour of draining from a pulley and some squeezing. No more sparging.
2. Started milling my grain. 0.025" vs store milled.
3. Bought a small recirculating pump which I start up while heating up the strike water and continue during entire mash.
What used to 1.050 OG is now 1.065 with the same grain bill. I could not believe my hydrometer reading the first time. But I have repeated this five times now.
Morrey
Well-Known Member
Are you using a heat source to keep your mash at stable temps while recirculating?
I'm a simpleton but here's what I've done with my BIAB brews over the last 6-7 years almost always hitting my numbers or higher----
I use Wilsner bags and since I have no way to lift 13 or more pounds of grain, I get two buckets, line them with 'painters' bags and use a double mesh strainer and strain 1/3 of the grains in one bucket, 1/3 in a second bucket and leave 1/3 in the BIAB bag. I squeeze the frack out of each and manage to get my volume and numbers right where they need to be. It really doesn't take much time as many who leave their bag hang for 10 minutes are so are taking the same time it takes me to do this.
I've found as I shake the mesh strainer each time I pull out the mash, it releases sugars. The squeezing does the rest and FWIW, (maybe my error in beersmith) my preboil is rarely what beersmith shows but my final gravity is usually spot on.
Hey, this has worked for me so I keep doing it but everyone has got to feel good about their process if they are making great beer.
I use Wilsner bags and since I have no way to lift 13 or more pounds of grain, I get two buckets, line them with 'painters' bags and use a double mesh strainer and strain 1/3 of the grains in one bucket, 1/3 in a second bucket and leave 1/3 in the BIAB bag. I squeeze the frack out of each and manage to get my volume and numbers right where they need to be. It really doesn't take much time as many who leave their bag hang for 10 minutes are so are taking the same time it takes me to do this.
I've found as I shake the mesh strainer each time I pull out the mash, it releases sugars. The squeezing does the rest and FWIW, (maybe my error in beersmith) my preboil is rarely what beersmith shows but my final gravity is usually spot on.
Hey, this has worked for me so I keep doing it but everyone has got to feel good about their process if they are making great beer.
Interesting.
Are you dividing up the grains while still in the mash kettle - or are pulling the bag out and doing that separately?
Morrey
Well-Known Member
You know, you said something that triggered off something I do that may be similar to your process. I often use an Arbor Fab mesh basket with a press plate. If I am pushed for time, I will press and move on. If I have more time or inclination, I'll take my stir paddle and lift up the grains, roll over the grain bed and press again. If I do this a couple of times I know my efficiency could be a bit higher say 80% w/o rolling to 83% by rolling over a time or two while pressing.
BigJoeBrew
Well-Known Member
I brew BIAB, and I dunk sparge every time that I brew. I have found with a normal (10)ish pound grain bill that dividing the water works well. I do 5 gallons at strike temp, which yields (4ish gallons) with a hell of a squeeze. After which I dunk sparge with 2.5 gallons knowing that I should yield 2.5 gallons since the grains have taken in all the water they can. But I still squeeze like hell again. No need to heat dunk sparge water since you are "rinsing" the grains (Thanks RM-MN). I will have to come back with gravity readings to show my results.
BrewManChoo
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After the mash, I do a quick drip drain of the bag into the wort (10lb grain bill wet is pretty heavy...so good little workout...it's too hot to squeeze with my hands at this point). Then I drop the grain bag into a bucket with an overturned mixing bowl at the bottom. This allows for a little collection reservoir at the bottom. I open my grain bag and spread it across the bucket opening, then pour water onto the grains, and poke it with my large mixing spoon, giving it plenty of time to drain out (maybe up to 30 minutes or so). Then, I pull the bag into a separate container, and pour the drippings into the boil kettle. I can give it plenty of drip time because I need time to get the wort to a full boil, and then even have another 60-90 minutes of full boil to play with.
By the end, I give the spent grains to my chickens, which they love, and it supplements my expensive chicken feed bill.
By the end, I give the spent grains to my chickens, which they love, and it supplements my expensive chicken feed bill.
TheBrewBag
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Whether you sparge with held back volume and then squeeze, or don't sparge and squeeze, the kettle efficiency will be the same because conversion is finite. Sparge brewers leave wort volume in the tun, and because they don't squeeze, an additional 7-8 oz of wort in the grain. If that volume was the same gravity as the kettle they could capture it the same way that you did by squeezing, but essentially they arrive at the same point as squeezers - but the lost volume in the tun dilutes the gravity below 1.020.
I don't believe you mentioned how much water you added to get the 1.020, but maybe you did. In either case there will always be trapped sugar that can be accessed by doing exactly what you did, but you'd have to dilute the existing wort to actually add it to the kettle.
I don't believe you mentioned how much water you added to get the 1.020, but maybe you did. In either case there will always be trapped sugar that can be accessed by doing exactly what you did, but you'd have to dilute the existing wort to actually add it to the kettle.
I'm against squeezing because it can add particulate that might burn on the bottom of the kettle.
I've been getting pretty good efficiency with this method :
Mash at target volume, not boil volume, biab style
After mash, lift bag place on a strainer over a clean, graduated bucket, siphon liquid and pass through grains to remove particulate. Allow to drain until it slows to a drip.
Check volume, determine how much to add for boil volume, and return liquid to kettle, turn on heat for boil.
Place grain bag /strainer over kettle and slowly rinse with enough water to come up to boil volume. Allow to drip as wort is coming up to a boil, then remove.
It may not be the fastest or easiest but it's not really labor intensive for a 5 gallon batch, and compared to expected gravity for traditional brewing I usually achieve the target unless I overestimated boil volume or just mashed too hot.
I've been getting pretty good efficiency with this method :
Mash at target volume, not boil volume, biab style
After mash, lift bag place on a strainer over a clean, graduated bucket, siphon liquid and pass through grains to remove particulate. Allow to drain until it slows to a drip.
Check volume, determine how much to add for boil volume, and return liquid to kettle, turn on heat for boil.
Place grain bag /strainer over kettle and slowly rinse with enough water to come up to boil volume. Allow to drip as wort is coming up to a boil, then remove.
It may not be the fastest or easiest but it's not really labor intensive for a 5 gallon batch, and compared to expected gravity for traditional brewing I usually achieve the target unless I overestimated boil volume or just mashed too hot.
geezerpk
Well-Known Member
I like your style!
pricelessbrewing
Brewer's Friend Software Manager
Absolutely disagree.
This is a matter of lauter efficiency, which is separate from conversion. Saying lauter efficiency doesn't matter would mean that squeeze and sparging don't influence mash or brewhouse efficiency at all.
At work but I'll try and remember to finish cleaning up the efficiency model spreadsheet which might help show why it's all just a matter of dilution.
I remember reading DeathBrewer's technique that dunking the drained/squeezed bag in water at 160F gave additional conversion if left for some time.
pricelessbrewing
Brewer's Friend Software Manager
Only if your conversion isn't complete in the first place. You're going to have lower attenuation from any additional conversion that occurs at 160F as beta enzymes denature extremely quickly at that time, so you're left with long chain dextrins, which will lead to a slightly higher fg, and slightly lower abv but not really any difference in body or sweetness (according to more recent research).
Instead I would recommend adjusting the crush, mash pH, and dough in processes to accelerate your conversion rate so that a mashout is not needed. This will provide better control and consistency. Further reading on my blog if you're inclined.
Alright, here's an updated spreadsheet using the wort volume and gravity points model. Pretty much every brewer is familiar with gravity points, so this is a natural extension which is nearly as accurate (~0.01 percent difference) as the much more convoluted "extract weight" method. The main hangup that noone has done this so far, was that it relied on the extract method for the initial step, because we need to know the mash gravity and the mash WORT volume. As I've stated previously, mash wort volume > mash water volume as the sugar (and proteins, dextrins, glucans etc) dissolved into the water it increases volume.
Link to spreadsheet
It really is as simple as a sponge in a pot of sugar water.
If you squeeze it, you'll get more sugar water out at X gravity.
If you then batch sparge it, the gravity will be lower in the sugar water, and in the sugar water that's trapped in the sponge because we can assume that the sugar is being dissolved evenly throughout the entire liquid (sparge volume + trapped volume).
If you don't squeeze it again, you're leaving a known volume of sugar water in the sponge. If you never sparged it, you're leaving a known volume of sugar water, at a higher gravity, in the sponge.
You can get additional conversion only if conversion is incomplete when you start the sparge, and if you haven't denatured the enzymes by doing a mash-out. Once the conversion is complete, it doesn't matter what you do, you can't get any more conversion. However, even after conversion is complete (no starch left) the enzymes can continue to work on (non-limit) dextrins to create a more fermentable wort.
Brew on
I'm dividing from the main bag in the kettle into 2 other bags in buckets. You can likely get by with just 1 bucket/bag if you have under 10 lbs.
This all started because I couldn't lift a bag full of wet grain and it just worked out that it helped my efficiency.
lawdawg
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I have been BIAB brewing for 3 years (actually it's the only method I've ever done other than a couple of partial mash attempts) and from my experience the squeezing only seems to benefit in hitting pre-boil volumes. I used to let my mash time go for about 1.5 hours to help out in hitting my pre-boil gravity but lately I've noticed that about 60-75 minutes is sufficient for getting close to my pre-boil gravity. Then, I raise the wort temp to around 168ish and essentially do a 10 minute mashout which usually allows me to hit or go slightly over my pre-boil gravity. Plus it saves me a few minutes on the overall brew day. My method for raising mash temp is to suspend the bag off the bottom of the pot with my ghetto pulley system and then fire the burner. This allows the wort to heat up to mashout temp without scorching the bottom of the bag. So, in my opinion the mashout is more effective at getting a bit more of sugars out of the grain although I'm sure there is some sugar still remaining since I'm not sparging with clear water. This doesn't concern my though since I'm hitting my gravities and usually making some pretty good beers. I really do just believe that the bag squeezing is just a last chance effort to help hit the preboil volume. Thanks for starting this post. I've enjoyed sharing some of my experiences doing BIAB. I'm a firm believer in it. It's how I got started and not planning to change other than to improve on some techniques and processes. It's simple and effective and less clean up. Hopefully this helps somebody out. Cheers!
I love seeing how there are so many variations that folks are using for BIAB.
I plan on trying a few of them to see if I get any sort of bump...
I plan on trying a few of them to see if I get any sort of bump...
OP
OP
This just reinforces for me the idea that brewing is actually a pretty resilient process, provided one takes care of the basics. There sure are a lot of variations on the theme, aren't there?
SlitheryDee
General Manager
Ok, so I did the first experiment I proposed earlier. I made a beer with a very simple grain bill that I mashed in 3.5 gallons of water, followed by a dunk sparge in 3.5 gallons of water. I squeezed the bag when I lifted it out of the mash water, then again when I lifted it out of the sparge water. I took gravity measurements at more or less every step.
I almost feel like I screwed something up though. I was extremely meticulous with all my measurements, moreso than I have been on any previous beer, yet my efficiency came out unbelievably high. I also stirred vigorously before taking my samples to hopefully minimize any stratification of the wort into multiple layers of differing densities, so that shouldn't be an issue. I'd be the first to congratulate myself for it if I actually thought it was accurate, but I don't really trust it. I'd appreciate it if anyone could find where I messed up and let me know lol.
The recipe:
Dunk 'n Squeeze Blonde
8.25lbs pale 2 row
2lbs minute rice
.5oz crystal (boil 60 min)
.5oz Willamette (boil 60 mins)
mash in 14 quarts of water for 60 minutes at 150F
Heat 14 quarts of water to 168 while mashing
At the conclusion of the mash squeeze out grains and drop them into the bucket of 168 degree sparge water.
Stir once, wait 10 minutes, stir again, then lift bag out
Squeeze bag until you're at 14 quarts again
Combine worts in boil pot
Boil 60 minutes adding hops as per schedule
Cool wort, add to fermenter, pitch yeast when ready
I had beersmith set to 75% efficiency because that was about what I hit on my last brew day. At that efficiency the numbers are:
OG - 1.050
Bitterness - 16.6 IBUs
Color - 3.5 SRM
ABV - 5.3%
Batch size - 5.42 gallons
The slightly weird batch size is there because it's what I needed for beersmith to give me my 3.5 gallon sparge amount. I wanted what I was doing to be reflected as accurately as possible in beersmith. To that end, I also changed the grain absorption rate to the same as it would be in BIAB since I would be squeezing the grains.
That's the grains, carefully measured on a kitchen scale to be exactly 10.25lbs.
I knew getting my water volumes correct was going to be important, so I used this precision measuring device to draw my mash and sparge water.
Shown here is me filling it up with my fancy new water filter. This IS my first brew using filtered water, but I can't see how that would make such a large difference in efficiency.
I knew I was on to something when I pretty much nailed my mash temperature. I forgot to take a picture of the post mash temp, but it was 144 degrees, or a 6-7 degree loss over 60 minutes. I chalk that up to the low volume of the mash. The full volume mash that will eventually make up the second half of this experiment should retain heat better.
Now for the good stuff. This is the post mash gravity AFTER squeezing the bag, but BEFORE any sparge water was added. This already seemed a bit high to me. That 1.076 measurement was also taken at 100F, so it converts to 1.081 at the hydrometer's calibration temp. Any idea what's going on there?
This is the gravity of my sparge water after removing the bag, but before squeezing the bag. Now the reason it's higher than mongoose's is likely because I put the grains in, stirred, left them for 10 minutes, stirred again, and then removed the bag. A bit more than just a dunk, but I wanted to give the process a fair shot. That sample was measured at 106 degrees, so it converts to 1.024 at the hydrometer's calibration temp. Not bad
This is the sparge water AFTER squeezing the bag to recover my water volume. It looks very close to the pre squeeze number, likely because of all the stirring and the 10 minute rest I gave it. I'm calling that one 1.020, which converts to 1.026 at the hydrometer's calibration temp.
This is the combined wort, or essentially the preboil gravity. 1.046 would be right in range normally, but if you take into account the fact that this measurement was taken at 98 degrees it becomes 1.051 at the hydrometer's calibration temp. That's already more than the post boil gravity is supposed to be! I definitely knew something was up at this point.
and finally the post boil gravity. I failed to record the temperature that this measurement was taken at, but considering that I took the sample and placed it in the fridge for a little while before measuring it, I'm guessing it was somewhere in the 70-80 degree range. It could be a couple of points in either direction, so I'll just call it 1.064.
So my numbers are as follows:
Strike gravity - 1.081
pre-squeeze sparge gravity - 1.024
Post squeeze sparge gravity - 1.026
Pre boil gravity - 1.051
OG - 1.064
When I input these numbers into beersmith, it says that I've achieved a whopping 95% efficiency. My volumes ended up right, with a little less than 5.5 gallons in the fermenter. Everything was measured to the best of my abilities, and I didn't really do anything that special. Can anyone account for this?
I almost feel like I screwed something up though. I was extremely meticulous with all my measurements, moreso than I have been on any previous beer, yet my efficiency came out unbelievably high. I also stirred vigorously before taking my samples to hopefully minimize any stratification of the wort into multiple layers of differing densities, so that shouldn't be an issue. I'd be the first to congratulate myself for it if I actually thought it was accurate, but I don't really trust it. I'd appreciate it if anyone could find where I messed up and let me know lol.
The recipe:
Dunk 'n Squeeze Blonde
8.25lbs pale 2 row
2lbs minute rice
.5oz crystal (boil 60 min)
.5oz Willamette (boil 60 mins)
mash in 14 quarts of water for 60 minutes at 150F
Heat 14 quarts of water to 168 while mashing
At the conclusion of the mash squeeze out grains and drop them into the bucket of 168 degree sparge water.
Stir once, wait 10 minutes, stir again, then lift bag out
Squeeze bag until you're at 14 quarts again
Combine worts in boil pot
Boil 60 minutes adding hops as per schedule
Cool wort, add to fermenter, pitch yeast when ready
I had beersmith set to 75% efficiency because that was about what I hit on my last brew day. At that efficiency the numbers are:
OG - 1.050
Bitterness - 16.6 IBUs
Color - 3.5 SRM
ABV - 5.3%
Batch size - 5.42 gallons
The slightly weird batch size is there because it's what I needed for beersmith to give me my 3.5 gallon sparge amount. I wanted what I was doing to be reflected as accurately as possible in beersmith. To that end, I also changed the grain absorption rate to the same as it would be in BIAB since I would be squeezing the grains.
That's the grains, carefully measured on a kitchen scale to be exactly 10.25lbs.
I knew getting my water volumes correct was going to be important, so I used this precision measuring device to draw my mash and sparge water.
Shown here is me filling it up with my fancy new water filter. This IS my first brew using filtered water, but I can't see how that would make such a large difference in efficiency.
I knew I was on to something when I pretty much nailed my mash temperature. I forgot to take a picture of the post mash temp, but it was 144 degrees, or a 6-7 degree loss over 60 minutes. I chalk that up to the low volume of the mash. The full volume mash that will eventually make up the second half of this experiment should retain heat better.
Now for the good stuff. This is the post mash gravity AFTER squeezing the bag, but BEFORE any sparge water was added. This already seemed a bit high to me. That 1.076 measurement was also taken at 100F, so it converts to 1.081 at the hydrometer's calibration temp. Any idea what's going on there?
This is the gravity of my sparge water after removing the bag, but before squeezing the bag. Now the reason it's higher than mongoose's is likely because I put the grains in, stirred, left them for 10 minutes, stirred again, and then removed the bag. A bit more than just a dunk, but I wanted to give the process a fair shot. That sample was measured at 106 degrees, so it converts to 1.024 at the hydrometer's calibration temp. Not bad
This is the sparge water AFTER squeezing the bag to recover my water volume. It looks very close to the pre squeeze number, likely because of all the stirring and the 10 minute rest I gave it. I'm calling that one 1.020, which converts to 1.026 at the hydrometer's calibration temp.
This is the combined wort, or essentially the preboil gravity. 1.046 would be right in range normally, but if you take into account the fact that this measurement was taken at 98 degrees it becomes 1.051 at the hydrometer's calibration temp. That's already more than the post boil gravity is supposed to be! I definitely knew something was up at this point.
and finally the post boil gravity. I failed to record the temperature that this measurement was taken at, but considering that I took the sample and placed it in the fridge for a little while before measuring it, I'm guessing it was somewhere in the 70-80 degree range. It could be a couple of points in either direction, so I'll just call it 1.064.
So my numbers are as follows:
Strike gravity - 1.081
pre-squeeze sparge gravity - 1.024
Post squeeze sparge gravity - 1.026
Pre boil gravity - 1.051
OG - 1.064
When I input these numbers into beersmith, it says that I've achieved a whopping 95% efficiency. My volumes ended up right, with a little less than 5.5 gallons in the fermenter. Everything was measured to the best of my abilities, and I didn't really do anything that special. Can anyone account for this?
BigJoeBrew
Well-Known Member
Great work SlitheryDee! I have had that exact same result on a Cream or 3 crops recipe. My process is exactly as you describe with even strike and dunk sparge methods. I also give 2 stirs during sparge. I am sure that grain crush like many BIABers know has a big effect. Do you mill your own grains? What kind of mill and what setting did you use? I have a knock-off corona mill and have really no control over milling.
SlitheryDee
General Manager
The grains I used came premilled from morebeer. It seemed like a fairly fine crush, but I don't have enough experience to say for sure.
Your numbers look pretty reasonable to me. Assuming 37 ppg for your 2-row and 32 ppg for your rice, the weighted ppg for your grain bill is 36 ppg. If I plug your volumes into my mash/sparge simulator, I come up with a max first runnings SG of 1.0857, and your 1.081 puts your conversion efficiency at ~94% (at the end of your mash.) You don't state your first runnings volume (or total pre-boil volume) so I assumed 0.07 gal/lb grain absorption, which estimates your first runnings volume at 2.78 gal. Your predicted sparge runnings SG came out at 1.022, and your pre-boil gravity at 1.048. The fact that your sparge SG and pre-boil SG were a little higher than predicted indicates that you probably got some additional conversion during the sparge step, since you weren't 100% converted at the end of your mash. The assumed grain absorption/first runnings volume could also throw the simulation off, if they are different than your actuals. I get your lauter efficiency at ~91% and your mash (pre-boil) efficiency at 85 - 86% (but probably a little higher if you really did get some additional conversion during the sparge.)
Brew on
pricelessbrewing
Brewer's Friend Software Manager
Re Efficiencies: What doug said.
Regarding volume measurements, measuring out 1 gallon at a time is pretty good, and likely better than most brewers, but it still leaves you with an instrumental uncertainty of around a half gallon for each 14qt water addition. Weighting it would be the best approach, but aside from that using a cylindrical volume calculation and measuring the height of the water at room temp.
I personally do not trust hydrometer temperature correction formulas, so I would add an additional 2-3% to all of your efficiency calculations uncertainty and put it at 83-88% mash efficiency.
Anytime you measure gravity, you also need to measure volume and temperature. You need an accurate measurement of all three at every step in order to analyze precisely, which is why I recommend filling out my form instead of beersmiths (or even worse, brewersfriend).
Playing around and experimenting is always good but here are my two cents;
BIAB as a process has several advantages over other techniques and the priimary one is simplicity. At full volume mash, no sparge, you just pull the bag and squeeze then discard the grains and move on with your life. If you use a ratcheting pulley, you don't need to use brute force or any other filters, buckets, or strainers. The next most important advantage of BIAB is mash pH stability (relative to sparging methods). If you don't take water chemistry and grist acidity into account at all (yet), sparging with poor pH conditions will only make a bad or borderline situation worse simply to chase a couple extra points of efficiency. It's not worth it.
There's nothing wrong with dunk sparging (batch sparging) but it's more hands on and requires more figuring and steps. If you like that, awesome. I like to walk away for an hour during the mash.
BIAB as a process has several advantages over other techniques and the priimary one is simplicity. At full volume mash, no sparge, you just pull the bag and squeeze then discard the grains and move on with your life. If you use a ratcheting pulley, you don't need to use brute force or any other filters, buckets, or strainers. The next most important advantage of BIAB is mash pH stability (relative to sparging methods). If you don't take water chemistry and grist acidity into account at all (yet), sparging with poor pH conditions will only make a bad or borderline situation worse simply to chase a couple extra points of efficiency. It's not worth it.
There's nothing wrong with dunk sparging (batch sparging) but it's more hands on and requires more figuring and steps. If you like that, awesome. I like to walk away for an hour during the mash.
I don't know that you'll give up any efficiency with the full-volume-no-sparge method. (still trying to wrap my head around this) When you sparge, you have less water in the mash so the first runnings are more concentrated. And the sugar left behind in the grist is more concentrated. Sparging extracts some of that sugar but not all of it. With the full-volume mash, the sugar is much more diluted -- then you don't even try to extract what's left in the grain.
I suspect when you sparge you extract more total sugar. (higher efficiency) But it might not be as much as one would think. And it certainly adds extra steps and requires more equipment, even if that equipment is just a bucket.
I'm going to try no-sparge with my next batch. But I don't have a control to make it a proper scientific test.
SlitheryDee
General Manager
I don't know that you'll give up any efficiency with the full-volume-no-sparge method. (still trying to wrap my head around this) When you sparge, you have less water in the mash so the first runnings are more concentrated. And the sugar left behind in the grist is more concentrated. Sparging extracts some of that sugar but not all of it. With the full-volume mash, the sugar is much more diluted -- then you don't even try to extract what's left in the grain.
I suspect when you sparge you extract more total sugar. (higher efficiency) But it might not be as much as one would think. And it certainly adds extra steps and requires more equipment, even if that equipment is just a bucket.
I'm going to try no-sparge with my next batch. But I don't have a control to make it a proper scientific test.
I forgot to mention earlier that I think the biggest reason my sparge water had such a high gravity most likely is the fact that the sugars I was washing out of the grist were much more concentrated than in the test mongoose performed. I found it interesting to note that my first runnings were probably high enough to come close to hitting my numbers without sparging at all, rather I could have just added 3.5 gallons of clean water and been at ~70% efficiency already. That also tells me that in this case the sparge made a huge difference in my perceived efficiency, most likely because of the more concentrated wort that was washed out of it.
Yeah my next brew will be the same grain bill as earlier, but with the full volume of water and no sparge. Pricelessbrewing has a good point about the potential cumulative error in my water volumes, but I figure if I use the same equipment at least the two brews will be comparable to each other if not to anyone else's. Then I might have something more definitive to say about the relative merits of full volume vs. dunk sparging.
lawdawg
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Hey SlitheryDee, what did you have the trub loss set to in Beersmith in the volume tab? With your grain bill I think you should have had closer to 7.5 gallons of total water. Maybe a little under 7.5. That may be why your gravities were so high. If you used a 1/2 gallon more water and didn't squeeze the bag dry then you still would probably have hit closer to the 1.050 and still had about 5.5 gal into the fermenter. Thanks for posting your experiment results.
SlitheryDee
General Manager
My trub loss is always set to 0 because I dump everything into the fermenter. Normally I would have used more water because I would be shooting for a particular batch size I suppose, but the batch size didn't really matter to me on this brew. I had specific numbers in mind for my mash volume and sparge volume and I was willing to accept whatever batch size resulted from that. The only concern I had was that what I was doing was accurately reflected in beersmith so that I could check my results against it's predictions, see it's measurements of my efficiencies, and generally record my session in a meaningful way. I settled on 7 gallons of water because it was a nice round number that could easily be divided in half while still getting me into the neighborhood of a regular batch size.
You absolutely do give up lauter efficiency if you don't sparge, and it can be mathematically proven. Your analysis in your first paragraph of what's going on with sparge vs. no-sparge is correct, but you need to attach some values to determine which extracts more total sugar (i.e. is higher efficiency.) In the example below I'll use weights instead of volumes, just to avoid having to convert concentrations to SG's in order to convert between volumes and weights.I don't know that you'll give up any efficiency with the full-volume-no-sparge method. (still trying to wrap my head around this) When you sparge, you have less water in the mash so the first runnings are more concentrated. And the sugar left behind in the grist is more concentrated. Sparging extracts some of that sugar but not all of it. With the full-volume mash, the sugar is much more diluted -- then you don't even try to extract what's left in the grain.
I suspect when you sparge you extract more total sugar. (higher efficiency) But it might not be as much as one would think. And it certainly adds extra steps and requires more equipment, even if that equipment is just a bucket.
I'm going to try no-sparge with my next batch. But I don't have a control to make it a proper scientific test.
Suppose you have a mash that contains 10 lbs of sugar and 90 lbs of water (about 11 gal.) That mash is 10 weight percent sugar, or 10˚Plato. If you collect 90 lbs of that wort (10 lbs left to grain absorption), you have 90 lbs of 10% sugar wort, or 9 lbs of sugar. This is the no sparge case. If instead, you start with 10 lbs of sugar and 45 lbs of water in the mash you have 55 lbs of wort at 100% * 10 / 55 = 18.2% sugar, if you collect 45 lbs of that wort you collect 45 * 0.182 = 8.182 lbs of sugar, leaving 1.818 lbs of sugar in the mash. Then you add 45 lbs of sparge water, so you again have 55 lbs of wort in the mash, but now the sugar concentration is 1.818 / 55 = 3.3%. You now collect 45 lbs of this sparged wort, and 45 * 0.033 = 1.488 lbs of sugar. Your total sugar collected when sparging is 8.182 + 1.488 = 9.67 lbs of sugar. Your lauter efficiency went from 9 lbs / 10 lbs = 90% to 9.67 lbs / 10 lbs = 96.7%.
I have put the above calculations in a spreadsheet, that also does the volume/weight conversions, and allows for variable grain bills, grain absorption rates, pre-boil volume targets, undrainable mash tun volumes, etc. I have run the calculations on a range of input parameters and the result is the chart below. It turns out that for a given grain absorption rate, and number of sparge steps, the lauter efficiency only depends on the ratio of the grain bill weight to the pre-boil volume, so the chart works for any batch size.
0.12 gal/lb grain absorption is typical for a traditional MLT. 0.10 gal/lb is typical for no-squeeze BIAB, 0.08 gal/lb for moderate squeeze, 0.06 gal/lb for aggressive squeeze, and 0.04 gal/lb for super-human squeeze. For the sparge cases, squeezing level is assumed to be the same post initial drain and post sparge drain.
I've posted this chart so many times all over HBT, that I was surprised to find that I hadn't already posted it in this thread.
Brew on
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