Is Sparging Obsolete?

[thekraken]

Would you list the bill of materials with cost and source for us? I haven't seen any 15 gal coolers for $45, much less with plumbing. If you have a reliable source, I'm sure many people on this forum would be interested. If you're buying used, then yes, diligent scrounging is usually much cheaper than buying new. But, it's unfair to compare new, custom made/fit to used. You also don't have to buy a custom made bag. Many people use very inexpensive paint strainer bags from HD, Lowes, etc. But, I really like my bag from Wilser.

Brew on

I made this:
https://www.homebrewtalk.com/f51/60qt-ice-cube-mash-tun-build-cheap-simple-144475/

I spent $26.46 at Walmart for the cooler, $13.59 at home depot for a ball valve and hose barb, and $4.72 at Lowes for the cpvc manifold materials.

-- Edit --

I built one for my self and the one for a friend, I'm happy with it. But this thread does have me wanting to try biab, at least for small batches.

-- Edit Edit --
BTW: That cooler is listed cheaper on walmart's website than in stores by like $5. I had to ask the clerk to match their own online price when I was at the register.

 

[RM-MN]

Lol....you guys are out of hand. The best is having the ability to do both. I haven't biab'd yet but I'm glad I know I can and really the idea of not watching gravity at the end of sparge is starting to be more appealing every brew.

Brewing is a pain in the a$$.

Not at all, brewing is fun and you get to drink the product. Today I brewed a double chocolate stout, only 10 minutes to mash, overshot my predicted OG and had more wort than I expected too because I sparged a little too much. About 2 hours, give or take from equipment and grains on the table to wort in the fermenter for no chill and everything put away.

 

[normonster]

Not at all, brewing is fun and you get to drink the product. Today I brewed a double chocolate stout, only 10 minutes to mash, overshot my predicted OG and had more wort than I expected too because I sparged a little too much. About 2 hours, give or take from equipment and grains on the table to wort in the fermenter for no chill and everything put away.

Don't lie....it was a burden for you...I know.

 

[ArkotRamathorn]

I do BIAB and I think even if I had a real nice big 8 or 10 gallon kettle, I would still dunk and rinse method. Once I look at 15 minutes left on my mash, I already have another smaller kettle (that I realized really quickly would never ever ever work for 5 gallon batches, but works perfect for heating sparge water) filled with 2-2.5 gallons of sparge water heating.

Since I have to wait for the grain to drain anyway, throw some hot water on top and help wash it all out. I just make sure I set up my process and day that I'm doing multiple things concurrently, waiting for the sparge water to wash through and drain isn't that big of a deal because I'm cleaning other stuff or measuring hops or updating my notes.

If I ever updated my equipment to do 10 gallon batches for example, its not like my older equipment (6.5 gallon kettle and a 5 gallon kettle) will still be there and can be used. So I'll still dunk and rinse sparge my stuff if it means I'm controlling my volumes and efficiency the way I'm expecting them to turn out (since improving my sparging techniques my efficiencies and volumes are finally starting to hit what I'm expecting).

 

[ArkotRamathorn]

I normally don't double post, but when I do it's because I thought of a good analogy.

The question shouldn't be "is it obsolete". I think people should ask "is it inefficient".

For me, no longer sparging would be an expensive choice as I would have to get a new kettle and I have no intentions of getting a new kettle for now, if I am gonna spend 200 or 300 dollars I am gonna spend it on other stuff like some bulk grains, more fermentation vessels, or parts for kegging. But do I need to spend that? No, my process works and I get my numbers.

Think of it this way. Let's say you have a 1992 Volvo, runs just fine, doesn't need maintenance that often, gets decent gas mileage. Would you replace this car just because it's obsolete compared to a more modern car that's 22 years newer? I wouldnt, spend 20,000 on a new car to replace something that works just fine? No thanks, obsolete wouldn't be the best word to use, if you consider it inefficient for your brewing and you spend the money to be able to full volume mash then you found that sparging was inefficient. For me the cost of switching to full volume would be an inefficient way for me to spend money when my process that includes sparging rarely takes me more than 4 hours without cleaning for a 5 gallon batch. If my brew day takes longer I am happy I get that much more quiet time, drink a scotch or a burboun and read my book while I wait for the boil or mash or draining the grain.

If it ain't broke, why fix it?

 

[doug293cz]

I made this:
https://www.homebrewtalk.com/f51/60qt-ice-cube-mash-tun-build-cheap-simple-144475/

I spent $26.46 at Walmart for the cooler, $13.59 at home depot for a ball valve and hose barb, and $4.72 at Lowes for the cpvc manifold materials.

-- Edit --

I built one for my self and the one for a friend, I'm happy with it. But this thread does have me wanting to try biab, at least for small batches.

-- Edit Edit --
BTW: That cooler is listed cheaper on walmart's website than in stores by like $5. I had to ask the clerk to match their own online price when I was at the register.

Thanks for responding. That's a good price for that cooler. Cheapest on Amazon (with shipping) was ~$62. I try to avoid Walmart. Looks like my bias can cost me some money.

From the pictures, it looks like the drain outlet is not all the way at the bottom of the cooler. Is that the case, or is it just an illusion? If the drain isn't at the bottom, what's the dead volume of the mash tun?

Brew on

 

[b-boy]

BIAB makes sense. I have no problem with it. if you want to do it, great. If it makes good beer for you, great.

I've thought about doing BIAB during the winter. It's tough to brew in my garage in February in 5F temperatures. I could probably do a BIAB for a small batch though. It would simplify the process and minimize the equipment I'd need.

What I hate are the BIAB mantras that go something like this:
"I do BIAB. I only have to mash for 32 seconds and I get 123% efficiency every time. I only spent $3.76 on my equipment. Everyone else is an idiot. You should ignore 1000 years of beer-making process because some guy broke his cooler and had to use a pillowcase to drain his wort. Did I mention that everyone else is an idiot?"

Reality - There are 20 ways to do everything. Everybody has their own best practice. If BIAB works for you, then do it. If you prefer batch sparging, then do it.

I mean we all know that the only people who don't now what the hell they're doing are the fly spargers - right?

 

[normonster]

Pillow case!!! Brilliant!

 

[giraffe]

Im confused about something though. When I mash, I target 5.2-5.5 ph depending on beer and sparge with 6.0. If you no sparge BIAB, wouldnt you have to have the ph of all 7 gallons of the water to 5.4 or whatever? If this is the case wont the ph of the beer be different to the fermenter, and in the final beer? What is the effect of this?

 

[rekoob]

This was a lot of time reading this thread I won't get back.

I really have nothing to add to the "topic". Do what you want. I would appreciate some actual research info if you try to pass the thread off as something you know about.

sparge, don't sparge... either way it makes beer, just a matter of how much extra stuff you want to add. right?

Okay, now back to the BIAB discussion at hand... oh, I forgot to add my hours/gallons info... maybe on another thread...

 

[thekraken]

Thanks for responding. That's a good price for that cooler. Cheapest on Amazon (with shipping) was ~$62. I try to avoid Walmart. Looks like my bias can cost me some money.

From the pictures, it looks like the drain outlet is not all the way at the bottom of the cooler. Is that the case, or is it just an illusion? If the drain isn't at the bottom, what's the dead volume of the mash tun?

Brew on

I'm worried we're veering off topic. It is above the bottom but the manifold siphons from the very bottom. Draining water alone leaves only about 0.5 to 2 cups behind, I haven't measured actual dead space on brew day.

 

[doug293cz]

I'm worried we're veering off topic. It is above the bottom but the manifold siphons from the very bottom. Draining water alone leaves only about 0.5 to 2 cups behind, I haven't measured actual dead space on brew day.

It's only marginally off topic. MLT dead space affects sparge efficiency (see my link earlier in this thread.) That's why it's best to minimize MLT dead space (reason I asked about yours), and also why it's best to squeeze the bag (if you're a squeezer) both before and after each sparge step.

Brew on

 

[jbaysurfer]

"First Brew was thanksgiving 2011, I'm at 99 batches and counting (as of 10/21/2014), and ran out of room in my signature to list them all."

Ouch!


I've obviously got some catching up to do..... at only 35 batches starting Feb 27 2014. I suspect I won't catch up until 2016. I won't even hit 50 this year. Saturday will be 36, and I'm making a shandy shooting for low attenuation to provide the sweetening for the fresh lemon I'll be putting in during "secondary". American Pilsner malt for a base.

It's not a contest. My signature line is for counting purposes only.

Brew day length, or preferred process is also not a contest.

 

[hunter_le five]

I don't know what all this sparge vs no-sparge / BIAB vs mash tun nonsense is about. Just do what I do and never separate the grain from the wort.

Beer, not unlike orange juice, is best served "extra pulpy".

 

[passedpawn]

I think BIAB is great, and no-sparge is great. It's all great. You're all superstars in my book!

Everyone's got their own situation, and requires a different setup. I brew big batches, sparges are necessary for sure.

Is sparging obsolete? Nope. But it is for the OP.

 

[helibrewer]

Nope.

 

[Calder]

No.

 

[orangemen5]

This was a lot of time reading this thread I won't get back. ...

+1
Couldn't even finish reading this thread.

 

[acidrain]

I actually thought this thread was going to be about full volume mash (according to the title), but after reading the body of the OP, I see it was clearly about starting a BIAB/traditional mash flame war.
Borderline trolling.

 

[kaconga]

I think what many people fail to realize is that mash ratios are just a tool. You can batch sparge or fly sparge or no sparge depending on what you want to do. It is like building a table. Some people will use nails, some screws, some will use cinder blocks. At the end of the day it will be a table regardless of the method you use. It is more about how you use the method you choose and not which method you choose.

 

[eko]

Ever read a thread that's 7 pages long and come out feeling like you know less at the end than you did when you started?

 

[paperairplane]

When I started, I read books. Reading about mashing sounds super complicated. Lots of math. Lots of variables. I need this amount of this temp water. If I miss temp, I need how much water at what temp? Then I need x amount of y temp water to sparge. What if it gets stuck.

It sounds very intimidating to a beginner. It sounds hard.

So I went full volume BIAB. It's a simpler process. For basic styles and gravity, it's virtually bulletproof.

Can I make a tridoproggenhefesteinlager, with a 7 stage decoction and 4 rests - no. But I can hammer out very legit pale ales, browns, stouts, wits and porters.

YMMV and RDWHAHB

 

[dobes]

Ever read a thread that's 7 pages long and come out feeling like you know less at the end than you did when you started?

Billy Madison!!! Luv it!!!

 

[VladOfTrub]

Though, the subject of sparge/no sparge is interesting, the quote below is interesting, too.

"RM-MN and I both are inclined to do extremely short mashes as well, and a few others are experimenting in that direction."

Who produces the malt you are using and what kind of malt is it that converts quickly? What is the temperature and pH of the mash during conversion? Since, you have been experimenting with enzymatic action, you probably have the info handy.

In the double stout, how did you determine full conversion occurred?

 

[pricelessbrewing]

If I can speak for rmmn, og was reached, starch test was passed, wort was no longer cloudy with starch are his usual indicators.

Not sure if either owly or rmmn test for ph but they use typical mash temps 145-150 or so.

Could be wrong, but I think they use american 2 row for their base malt. Not sure of they've used european pilsner or other less modified malts.


As for the thread topic, id love to not have to sparge for a 5 gallon batch but my 7.5 pot, height restriction between microwave and stovetop and stovetop heat output all limit me to about 6.5 pre boil and 7.5 mash volume.

Could probably find a larger pot that's shorter and wider but not sure how that would affect the stoves boiling power, more surface area means less vigorous boils.

 

[RM-MN]

Though, the subject of sparge/no sparge is interesting, the quote below is interesting, too.

"RM-MN and I both are inclined to do extremely short mashes as well, and a few others are experimenting in that direction."

Who produces the malt you are using and what kind of malt is it that converts quickly? What is the temperature and pH of the mash during conversion? Since, you have been experimenting with enzymatic action, you probably have the info handy.

In the double stout, how did you determine full conversion occurred?

To be honest, I didn't determine if the full conversion occurred in the double stout. Since I had experimented with the very short mashes before, I assumed that using the same base malt with nearly the same water and temperature would convert the same. The fact that I got higher OG than predicted should indicate that I did get full conversion. The question is whether I allowed enough time for the beta amylase to break down sufficient long chain sugars to short chain sugars that can be fermented by my yeast. For that, I have to wait until the beer is done and compare the FG with what was predicted.

I used Rahr malt for this batch and mashed at 152. I used an acid blend to bring my mash to the proper pH as I had tested this previously and found my pH to be a bit high. I did not test this batch for pH as with the acid that I added plus the dark grains it should have been within the proper range.

 

[djt17]

How much does a bag cost for biab? Looking at a few sites I googled (Like this one: http://www.brewinabag.com/) they seem to be charging $30-$35 for a bag. You gotta be able to find these cheaper right? It's just a mesh bag!

I paid $7 for this one: http://morebeer.com/products/bag-29-brew-biab.html 6 batches so far, works great!

 

[ArkotRamathorn]

To be honest, I didn't determine if the full conversion occurred in the double stout. Since I had experimented with the very short mashes before, I assumed that using the same base malt with nearly the same water and temperature would convert the same. The fact that I got higher OG than predicted should indicate that I did get full conversion. The question is whether I allowed enough time for the beta amylase to break down sufficient long chain sugars to short chain sugars that can be fermented by my yeast. For that, I have to wait until the beer is done and compare the FG with what was predicted.

I used Rahr malt for this batch and mashed at 152. I used an acid blend to bring my mash to the proper pH as I had tested this previously and found my pH to be a bit high. I did not test this batch for pH as with the acid that I added plus the dark grains it should have been within the proper range.

So has a lot of people done side by sides with quick mashes (say less than 20minutes) compared to the standard mashes in terms of mouth feel and flavor?

Out of curiosity mostly, if I brew a pot of oolong tea and I do the proper 90 seconds at 190ish F water, its really light and clean, floral depending on the variety. If I am being lazy and do a 212F water at 2 minutes, its completely different, minerally and astringent (still delicious but very very different). So has anyone found that theres some type of flavor development during a 20min vs 60min mash?

 

[Owly055]

Though, the subject of sparge/no sparge is interesting, the quote below is interesting, too.

"RM-MN and I both are inclined to do extremely short mashes as well, and a few others are experimenting in that direction."

Who produces the malt you are using and what kind of malt is it that converts quickly? What is the temperature and pH of the mash during conversion? Since, you have been experimenting with enzymatic action, you probably have the info handy.

In the double stout, how did you determine full conversion occurred?

I use Malteurop two row, made in Great Falls, Montana, but I don't think that's relevant. I suspect that most any good malt will convert very rapidly with a fine grist. I often crush with a roller spacing of .010, which requires a double crush, the first at about .025, and the second at .010. Conversion starts being noticable at about 150 , and is rapidly completed at around 155, where it seems to go almost instantly.
I dough in to hot tap water, and heat right up steadily on the stove top rather than doughing in at mash temp. I heat rapidly, then slow down at 145 to 1 deg per minute, considering that the beginning of my mash when doing a 10 min mash. This will give reduced attenuation amounting to about 3/4 of a percent alcohol less than a full mash, and a slightly richer sweeter product. I usually mash longer by heating more slowly, and / or doing a cold water splash down to the mid 140's and bringing it back up slowly. 20 minutes to 30 minutes is my usual mash, and will give the same attenuation as a full hour "normal" mash.
I determine conversion both using a refractometer, and doing iodine tests, but the clearing of the wort tells the tale..... You can see it happen. What you can't see is the beta amylase breaking down long chain sugars into fermentables. There really is no way I know of observing this.

H.W.

 

[steveoatley]

I mean we all know that the only people who don't now what the hell they're doing are the fly spargers - right?

stir the pot, once to the left, twice to the right, I get 5% more efficiency



S

 

[Owly055]

This really is about the benefits of sparging versus full volume, not conventional versus BIAB. Many BIAB brewers sparge, as I did at the beginning.

With a conventional mash and sparge, it is logical that the yield should be better.

The first wort is a very high percentage of sugar, and the grain bed should have the same percentage of sugar remaining. The second running will reduce the residual sugars, and come out at a much lower percentage, leaving the grain bed at that percentage. Combining the first and second runnings will give a mash with a percentage of sugar considerably higher than what is remaining in the grain bed. With each succeeding running, the sugars in the grain bed will be reduced and the sugars in the wort will be reduced, but the wort will always be higher.

That seems like a perfectly obvious equation, but you reach a point where you have to increase the boil.

Thus a full volume mash should NOT achieve as the recovery as a conventional mash and sparge.

BIAB, by eliminating the stuck sparge issue has allowed an extremely fine grist, and this seems to liberate more starch for conversion, hence the phenomenal efficiencies I have seen. Finer grist appears to liberate more starch to begin with, then if you sparge a bit, the "efficiency" can go into the mid 90's, but ONLY because the charts are based on a normal grist, so you are in effect "cheating". When my pot was too small, I sparged using a crude technique of simply pouring water from a sauce pan over the grain bag as it sat in a colander, thoroughly saturating it, then squeezing, and repeating the process until I hit my pre-boil volume....... This worked very well, but was time consuming. Using a fine grist, I'm hitting very close to 90%.... without sparging. The same thing could be done in a mash tun I suspect....... If you used enough rice hulls.

H.W.

 

[nutty_gnome]

I like BIAB. I've brewed a dozen 5 gallon batches with it. I also don't bother with a dunk sparge or a sprinkle sparge. But I am going to try a one gallon dunk sparge on the next batch. I usually get 70% eff.

And I believe the controversial '10 minute mash' stuff currently being tossed around on these forums ONLY has merit for very specific situations. Humans didn't define the Lintner Degree of measurement just for fun. They defined it because it matters. Some malts can effectively convert in 10 minutes. Some wont. If you can find ones that do convert quickly and you like the result, bravo for you.

But I don't think the 10 minute mash will ever be considered gospel or espoused in any credible brewing book. There are too many variables among all the systems and methods people use to definitively say a ten minute mash is the way to go.

 

[passedpawn]

BIAB, by eliminating the stuck sparge issue has allowed an extremely fine grist, and this seems to liberate more starch for conversion, hence the phenomenal efficiencies I have seen. Finer grist appears to liberate more starch to begin with, then if you sparge a bit, the "efficiency" can go into the mid 90's, but ONLY because the charts are based on a normal grist, so you are in effect "cheating".

I believe maximum potential extract for barley (e.g., 1.036) is calculated assuming laboratory extract, or fine grind, but not "normal grist".

I grind as fine as I can and I don't get stuck sparges. I've built my system to allow me to do that.

I don't ever believe other people's efficiency numbers. No offense, you might very well have the numbers you claim, but I have found that there are a lot of variables to accurately measure this, and I doubt most people are sweating those details since they are busier just trying to make the beer.

The point about accepting lower efficiency because grain is cheaper than propane is a good one, but don't assume everyone uses propane. I don't, and I know many others are also brewing with electricity. In the case of electricity, boiling for extended periods isn't really a cost factor.

 

[Owly055]

I believe maximum potential extract for barley (e.g., 1.036) is calculated assuming laboratory extract, or fine grind, but not "normal grist".

I grind as fine as I can and I don't get stuck sparges. I've built my system to allow me to do that.

I don't ever believe other people's efficiency numbers. No offense, you might very well have the numbers you claim, but I have found that there are a lot of variables to accurately measure this, and I doubt most people are sweating those details since they are busier just trying to make the beer.

The point about accepting lower efficiency because grain is cheaper than propane is a good one, but don't assume everyone uses propane. I don't, and I know many others are also brewing with electricity. In the case of electricity, boiling for extended periods isn't really a cost factor.

Good point about efficiency numbers..... Mine are taken at the fermenter. I use a hydrometer here....... the one and only time. I take the OG based on a hydrometer reading and match it to the numbers Brewer's Friend gives. If my OG is high, I simply adjust the efficiency number given in the program until the predicted OG matches my actual OG. Not very scientific. I don't think it makes sense to compare your efficiency to anybody else's for exactly the reason you mention. It's only useful within your own operation.


If you are using those barbeque bottles, you are paying a LOT for energy. Mine comes in a 1000 gallon bottle, and I paid $1.45 a gallon this year. This is FAR cheaper than electricity. I also have a couple 100 lb bottles (20 gallon) that cost $60 to fill these days. Far cheaper than the little bottles still. The pre filled bottles run about $5 per gallon.... an absurd price!

H.W.

 

[ArkotRamathorn]

Are we really going to get into the discussion of "saving" money by brewing beer? Yeah, excluding equipment and labor it's pretty cheap to make small beers.

But do a lot of us get into brewing thinking we are gonna save money on beer? Yes. Do we end up saving money on beer? Lol no (over time sure and if you buy a lot of bulk but, with how the brewing community is firmly in the gadget and experimentation column we don't truly save money cause there's always new things to buy)

I fill my 17lb propane tank for like 15 bucks. Do I try and figure out how much this costs me per batch? No. Does it worry me when I have a beer that needs a 90 minute boil? No. If it was a full tank each time I made a batch I'd look at ways to decrease my heating cost, but my latest tank is going strong on 8 batch, 2 of which needed 90 minutes because of Pilsner malt, 2 had 120 minute boils because I wanted kettle carmelization.

So do you brew beer to be efficient? Or do you brew beer to make tasty beer that you can point at and say "I made that"?

 

[doug293cz]

This really is about the benefits of sparging versus full volume, not conventional versus BIAB. Many BIAB brewers sparge, as I did at the beginning.

With a conventional mash and sparge, it is logical that the yield should be better.

The first wort is a very high percentage of sugar, and the grain bed should have the same percentage of sugar remaining. The second running will reduce the residual sugars, and come out at a much lower percentage, leaving the grain bed at that percentage. Combining the first and second runnings will give a mash with a percentage of sugar considerably higher than what is remaining in the grain bed. With each succeeding running, the sugars in the grain bed will be reduced and the sugars in the wort will be reduced, but the wort will always be higher.

That seems like a perfectly obvious equation, but you reach a point where you have to increase the boil.

Thus a full volume mash should NOT achieve as the recovery as a conventional mash and sparge.

BIAB, by eliminating the stuck sparge issue has allowed an extremely fine grist, and this seems to liberate more starch for conversion, hence the phenomenal efficiencies I have seen. Finer grist appears to liberate more starch to begin with, then if you sparge a bit, the "efficiency" can go into the mid 90's, but ONLY because the charts are based on a normal grist, so you are in effect "cheating". When my pot was too small, I sparged using a crude technique of simply pouring water from a sauce pan over the grain bag as it sat in a colander, thoroughly saturating it, then squeezing, and repeating the process until I hit my pre-boil volume....... This worked very well, but was time consuming. Using a fine grist, I'm hitting very close to 90%.... without sparging. The same thing could be done in a mash tun I suspect....... If you used enough rice hulls.

H.W.

When doing no sparge, the efficiency is determined by how much wort is left in the grain and the sugar concentration in that wort (this is the sugar left behind.)

Sugar_left_behind = Wort_left_in_grist * Sugar_Concentration_in_Wort​

Minimizing both terms on the right, minimizes the sugar left behind, which maximizes efficiency. (Maximize efficiency by minimizing loss)

The more water you use in the mash, the lower the concentration of sugar in the wort, thus less sugar in the wort left behind in the grist. And minimizing wort left in the grist (squeezing the bag) minimizes the sugar left behind, no matter what the concentration of sugar in the wort. So to maximize efficiency with no sparge we use full volume mash and squeeze. We all know this, but the above may be a slightly different way of thinking about it for some people.

When using a traditional MLT it is not possible to squeeze the grain bed (minimize the wort left behind.) Thus it is not possible to reduce the volume of wort left in the grain beyond what gravity draining provides. So to make up for the lack of ability to squeeze the bag, the brewer rinses the grain bed (sparges) to reduce the amount of sugar trapped in it. Sparging adds more total water to the wort, so to compensate, less water must be used in the mash. This results in higher sugar concentration in the wort trapped in the grain after first running, which make sparging even more of a necessity.

So, sparging is just a way for those who can't do full volume mashes and squeeze the grain bed to improve their efficiency

Brew on

 

[JustLooking]

So, sparging is just a way for those who can't do full volume mashes and squeeze the grain bed to improve their efficiency.

So, that explains why all the professional brewery's have presses built into their mash tuns to squeeze out every last bit of wort.

 

[TasunkaWitko]

This is starting to resemble a .308 vs. .30/06 thread.....

 

[ArkotRamathorn]

This is starting to resemble a .308 vs. .30/06 thread.....

Dude, a .308 is flatter at 500 yards than than .30/06. (I joke, any discussion of ballistics of the two is nonsense, if you shoot a deer with either one, theyll drop, and at less than 200 yards theyre exactly the same)

So this start to beg the question about the squeezing, is the whole squeezing tannins out a myth? Or, is it just, if you keep your PH at an acceptably low level you don't ahve to worry abou this?

 

[Owly055]

When doing no sparge, the efficiency is determined by how much wort is left in the grain and the sugar concentration in that wort (this is the sugar left behind.)

Sugar_left_behind = Wort_left_in_grist * Sugar_Concentration_in_Wort​

Minimizing both terms on the right, minimizes the sugar left behind, which maximizes efficiency. (Maximize efficiency by minimizing loss)

The more water you use in the mash, the lower the concentration of sugar in the wort, thus less sugar in the wort left behind in the grist. And minimizing wort left in the grist (squeezing the bag) minimizes the sugar left behind, no matter what the concentration of sugar in the wort. So to maximize efficiency with no sparge we use full volume mash and squeeze. We all know this, but the above may be a slightly different way of thinking about it for some people.

When using a traditional MLT it is not possible to squeeze the grain bed (minimize the wort left behind.) Thus it is not possible to reduce the volume of wort left in the grain beyond what gravity draining provides. So to make up for the lack of ability to squeeze the bag, the brewer rinses the grain bed (sparges) to reduce the amount of sugar trapped in it. Sparging adds more total water to the wort, so to compensate, less water must be used in the mash. This results in higher sugar concentration in the wort trapped in the grain after first running, which make sparging even more of a necessity.

So, sparging is just a way for those who can't do full volume mashes and squeeze the grain bed to improve their efficiency

Brew on

It is of course possible to squeeze.......... Empty your mash tun into a bag and squeeze.... But of course nobody does that. I've been threatening to collect the spent grains from my local microbrewer when he does a high gravity brew, and more or less do that. That is until he and I discussed doing a partigyle and I found that he adds DME to his high gravity brews........... so much for that idea ;-(. Still considering the fact that he does 15 barrel brews, I could probably squeeze enough wort out of the spent grains to make a good beer...... It might require a 2 or 3 hour boil though!

H.W.