Less efficiency with 11 gallon batches vs 5.5 in 15 gallon pot?

[NitrogenWidget]

So I brewed myself a 5 gallon batch of biermunchers centenial blonde.
It was great and I hit my numbers so I decided to brew a double batch and came in low on the OG even though I just doubled the grain bill.

I used the same mill on the same settings.
I thought it was because i had more than 11 gals. of wort (I had 12).

well, I brewed an 11 gallon batch of oktoberfast today. and came in low again on the OG. my efficiency is going down with larger batches.
I adjust the grain bill to reflect my standard 90% efficiency when doing 5.5 gallon batches then double it but am coming in low.
Should of come in at 1.051 but ended up with 1.045 not too much lower but still with the last 10 5.5 gal batches I hit my OG almost spot on every time.

Could this have anything to do with my 15 gallon kettle basically at the brim with grain in it?
Also, it's harder to squeeze a bag of 20lbs of grain than 10lbs but it shouldn't be that much of a difference.

 

[dansensel]

Did you increase your mash time? I would guess that you have a thicker mash with double the grain bill, as your boil losses are probably the same. Also, it is more likely with a larger grain bill, that you have some grain that isn't getting full conversion. I would add an extra 20 minutes to your mash and perhaps an extra stir of the mash to make sure you get all of the grain exposed to water.

 

[RM-MN]

So I brewed myself a 5 gallon batch of biermunchers centenial blonde.
It was great and I hit my numbers so I decided to brew a double batch and came in low on the OG even though I just doubled the grain bill.


Could this have anything to do with my 15 gallon kettle basically at the brim with grain in it?
Also, it's harder to squeeze a bag of 20lbs of grain than 10lbs but it shouldn't be that much of a difference.

I would guess that with the kettle that full you don't stir as well and probably have some grains that aren't getting wetted. Try starting with a smaller volume of mash water and adding a sparge step or simply topping up with water when the mash is done.

 

[Soulshine2]

Did you increase your mash time? I would guess that you have a thicker mash with double the grain bill, as your boil losses are probably the same. Also, it is more likely with a larger grain bill, that you have some grain that isn't getting full conversion. I would add an extra 20 minutes to your mash and perhaps an extra stir of the mash to make sure you get all of the grain exposed to water.

I would add "batch sparge" to this as well. Might not be getting all of your sugars out . With a double batch sparge or even a triple with a stir added , you'll get a much better efficiency.

 

[wilserbrewer]

Would a smaller boil off relative to boil volume decrease efficiency?

I wouldn’t think it would make a 10% difference?

But it could be substantial.

Say on a 6.5 gallon boil you boil off a gallon, and boil off the same amount on a 12 gallon boil?

Boil off tends to be more constant to the kettle than volume.

As for squeezing large grain bill, imo don’t bother, let the grain bag hang and drain for 30 minutes, I find this to be very effective.

Edit...scratch the nonsense above, boil off has nothing to do with efficiency, but could land a lower OG.

Edit edit...don’t scratch anything, lower relative boil off reduces the amount of total water which will increase gravity of the absorbed wort, combined with possible higher grain absorption???

Is your grist to water ratio higher on the larger batches? My guess is that you will be proportionally less efficient by that amount.

 

[doug293cz]

For a constant grain bill weight to pre-boil volume ratio (weight / pre-boil volume = constant), you should get the same mash efficiency (if the process is the same), if your grain absorption ratio (squeezing/draining process the same.) Inadequate stirring at mash in could reduce your conversion efficiency, which would reduce your mash efficiency. A lighter squeeze could reduce your lauter efficiency, which would also reduce your mash efficiency.

Was your grain wt to pre-boil volume the same for the small and large batch? If your large batch pre-boil volume was less than double the small batch volume, that would reduce your lauter efficiency a little bit.

Brew on

 

[NitrogenWidget]

I usually start with 6.5-7 gallons of water for a standard 5.5 gallon batch, I went with 13 gallons for the 11 gallon batch because I was afraid it wouldn't all fit in my 15 gallon pot.
I was right!

I whisked the grain as I added it in roughly 1 gallon amounts as it almost filled up a 5 gallon bucket after milling.
I did not stir it during the mash and mashed for 60 mins.
I did add water after the mash to top it back up to 13 gallons for 90 min. boil.
I ended up with 11 gallons perfectly.
5.5 per bucket.
So it isn't my water volume that is the issue.

My mill doesn't need adjustment either since I did a one gallon batch and came in as expected just before this big batch.

I think the bolded is probably the issue and with the larger amount of grain the middle was insulated from hot water?

 

[tennesseean_87]

That added water could be poured over the grain bag to help a little. I've done 4-8 gallon batches in a 15 pot and not noticed a correlation in efficiency, but I'm doing a recirculated eBIAB, so it's a different kettle of fish as far as stirring goes.

 

[NitrogenWidget]

Next double batch I’ll leave a few gallons out of the mash so I can whisk the grain better without burning my knuckles. Then after I pull the bag pour the gallons I need to hit volume for pre boil over the bag to see if that helps.

 

[NitrogenWidget]

oddly enough after almost 2 weeks the beer is down to 1.006 bringing ABV up to a little over 5%.
the sample I took was mighty tasty also.

Using kolsch yeast so it's got a few more weeks to go.
might get another point out of it since the krausin hasn't dropped yet.

 

[Hopalong]

Recipes and the numbers attached to recipes are inaccurate due to malt being very inconsistent. Before a recipe can be deemed accurate a spec sheet for the recommended malt needs to be looked at. A spec sheet comes with each sack of malt and it's used to determine the quality of malt.
There are two types of malt on the market, under modified, low protein malt which is used to make ale and lager and fully modified, high protein malt suitable for making whiskey and homebrew. When a recipe recommends using syrup, fully modified malt, single temperature infusion, only primary fermentation and adding priming sugar and CO2 for carbonation, the beer produced is similar in quality to Prohibition style beer not ale and lager styles of beer.
If a conversion rest was omitted no Oktoberfest was brewed. When a conversion rest is skipped the complex types of sugar needed to make ale and lager with aren't formed and the beer is known as Prohibition style beer. The rest is skipped in homebrew recipes because it adds two weeks on to the brewing schedule, but more so, the rest isn't required because fully modified malt lacks Beta amylase and to use the malt to make ale and lager an Alpha-Beta amylase mixture needs to be added and a conversion rest at 140 t0 145F is required to activate the enzyme. When conversion occurs the beer doesn't require the addition of priming sugar or CO2 for carbonation. The beer naturally carbonates when yeast works on maltotriose during aging/lagering. Natural carbonation is much finer than the soda pop fizz created by priming with sugar and injecting with CO2.

 

[KonservativeJay]

Give me source on this “prohibition style beer” you are so happy to downgrade homebrew to. Sources on ale requiring a decotion mash would be nice as well. And why not tell us what you think “highly modified malt” is?

 

[Lefou]

#11 is disjointed bot babble, in my opinion.

 

[tennesseean_87]

Recipes and the numbers attached to recipes are inaccurate due to malt being very inconsistent. Before a recipe can be deemed accurate a spec sheet for the recommended malt needs to be looked at. A spec sheet comes with each sack of malt and it's used to determine the quality of malt.
There are two types of malt on the market, under modified, low protein malt which is used to make ale and lager and fully modified, high protein malt suitable for making whiskey and homebrew. When a recipe recommends using syrup, fully modified malt, single temperature infusion, only primary fermentation and adding priming sugar and CO2 for carbonation, the beer produced is similar in quality to Prohibition style beer not ale and lager styles of beer.
If a conversion rest was omitted no Oktoberfest was brewed. When a conversion rest is skipped the complex types of sugar needed to make ale and lager with aren't formed and the beer is known as Prohibition style beer. The rest is skipped in homebrew recipes because it adds two weeks on to the brewing schedule, but more so, the rest isn't required because fully modified malt lacks Beta amylase and to use the malt to make ale and lager an Alpha-Beta amylase mixture needs to be added and a conversion rest at 140 t0 145F is required to activate the enzyme. When conversion occurs the beer doesn't require the addition of priming sugar or CO2 for carbonation. The beer naturally carbonates when yeast works on maltotriose during aging/lagering. Natural carbonation is much finer than the soda pop fizz created by priming with sugar and injecting with CO2.

I need to go read your other 50 posts. This is entertaining!

 

[Soulshine2]

I usually start with 6.5-7 gallons of water for a standard 5.5 gallon batch, I went with 13 gallons for the 11 gallon batch because I was afraid it wouldn't all fit in my 15 gallon pot.
I was right!

I whisked the grain as I added it in roughly 1 gallon amounts as it almost filled up a 5 gallon bucket after milling.
I did not stir it during the mash and mashed for 60 mins.
I did add water after the mash to top it back up to 13 gallons for 90 min. boil.
I ended up with 11 gallons perfectly.
5.5 per bucket.
So it isn't my water volume that is the issue.

My mill doesn't need adjustment either since I did a one gallon batch and came in as expected just before this big batch.

I think the bolded is probably the issue and with the larger amount of grain the middle was insulated from hot water?

why did you not stir it during the mash? Could have had dough balls or dead spots . I always stir a couple times during mash ,every 20 minutes, to make sure all of it gets circulated temperature wise .

 

[NitrogenWidget]

why did you not stir it during the mash? Could have had dough balls or dead spots . I always stir a couple times during mash ,every 20 minutes, to make sure all of it gets circulated temperature wise .

I BIAB on my deck with a propane burner in a 15 gal pot.
So when mash starts I throw an old sleeping bag and wool blanket over the pot and bungie cord it at the bottom.
Never had an issue with 5 gallon batches.
I don't know if i'll do another 10 gallon batch until spring since I want to try out some maltier brews for winter and that will be 5 gallon batches but I have a plan if I do another 10 gallon this winter.

Not go full mash because it brings my 15 gallon pot to the brim and makes a mess.
I will check OG after mash then adjust with water before boil planning for boil off.
I also think lower water level for mash will let me mix it up better before I seal it up for the mash.

 

[JONNYROTTEN]

Props to getting 90% efficiency...not even sure how thats possible but thats a mighty good number.
I brew full mash 12 gallon batches in a 20 gallon pot every brew and hit my numbers every time. With an normal grain bill of 25#'s or so I'm always within 2 inches of the rim after adding the grains. Usually less.
No clue how your doing 10 gallon full mash in a 15 gallon pot. It"almost" seems like your adding grains for a full 10 gallons and possibly actually having less water volume giving you a really high false 90% efficiency

As far as low efficiency
I would go with clumps from not stirring enough
or, a fluke bad crush,
or your water volume numbers are off.

If you want to do 12 gallon batches to leave you with a FULL 5 to 5.5 gallon brew I would suggest dropping around $100 for a 20 gallon pot. It makes life so much easier. Not even a chance of a boil over or over spill. use the pot you have for your 5 gallon brews

 

[NitrogenWidget]

Well i'm doing 10 gallon batches poorly apparently.
If I'm going to drop $100 for a pot 5 gallons more then I might as well go 30 gallon pot so I can brew 15 gallons at a time.
Then i'll probably need to upgrade my burner.......

 

[pretzelb]

Recipes and the numbers attached to recipes are inaccurate due to malt being very inconsistent. Before a recipe can be deemed accurate a spec sheet for the recommended malt needs to be looked at. A spec sheet comes with each sack of malt and it's used to determine the quality of malt.
There are two types of malt on the market, under modified, low protein malt which is used to make ale and lager and fully modified, high protein malt suitable for making whiskey and homebrew. When a recipe recommends using syrup, fully modified malt, single temperature infusion, only primary fermentation and adding priming sugar and CO2 for carbonation, the beer produced is similar in quality to Prohibition style beer not ale and lager styles of beer.
If a conversion rest was omitted no Oktoberfest was brewed. When a conversion rest is skipped the complex types of sugar needed to make ale and lager with aren't formed and the beer is known as Prohibition style beer. The rest is skipped in homebrew recipes because it adds two weeks on to the brewing schedule, but more so, the rest isn't required because fully modified malt lacks Beta amylase and to use the malt to make ale and lager an Alpha-Beta amylase mixture needs to be added and a conversion rest at 140 t0 145F is required to activate the enzyme. When conversion occurs the beer doesn't require the addition of priming sugar or CO2 for carbonation. The beer naturally carbonates when yeast works on maltotriose during aging/lagering. Natural carbonation is much finer than the soda pop fizz created by priming with sugar and injecting with CO2.

A lot going on in this post and I am not sure any of it is helpful.

 

[PersonalBrewer]

I went with 13 gallons for the 11 gallon batch because I was afraid it wouldn't all fit in my 15 gallon pot.

I have a fifteen gallon pot and routinely brew 11 gallons into two fermenters. Usually net about 9.5 gallons into two kegs.

I whisked the grain as I added it in roughly 1 gallon amounts as it almost filled up a 5 gallon bucket after milling.
I did not stir it during the mash and mashed for 60 mins.

You need to add probably about 10% more grains than simply doubling the recipe I have found. I think it's because there is less water in the mash. Stir the mash about every 20 minutes, thoroughly. I use a large whisk.

My grains for a 11 gal batch will usually almost fill two five gallon buckets.

Basically, I double a five gallon recipe, then add about 10% more on the grains. LHBS Shop mills them, I condition and mill at .025.

Mash in with about as much water as I can still stir, mash for minimum of 60, pull the bag, top off with water to 13.5 gallons for boil. I usually do a 90 minute boil, after the bag has drained into a five gallon bucket I pour that into the boil, make sure it gets at least an hour.

The only time I have ever had low ABV was when I hit too high a strike temperature by mistake.

This works for me just fine.

I've probably done ten or more large two keg batches this way. I've been quite happy with the process and beer that is produced.

I'm not that concerned about efficiency, I'm more concerned about flavor. Which is why I am now going to step infusion mashes, and made several recent posts in a thread related to that
https://www.homebrewtalk.com/forum/threads/biab-infusion-step-mashing.627255/

 

[NitrogenWidget]

Good stuff thanks

 

[PersonalBrewer]

You're welcome.

I'm starting with 11.25/11.50 gallons of water. After I stir in the grains if it looks like I can add a little water, I do. As much water as I can without spilling it over the side when I stir.

Warning, 30lbs of dry grain is going to weigh somewhere around 45/50 lbs when wet even if wort is squeezed/pressed out.

I use a rope and pulley to manage the weight.

I only keg and have never bottled. I got tired of putting five gallons into one keg and 2.5 in another.

With the added 10% of grains, you're getting a drop in efficiency. Which doesn't bother me that much when I'm getting one full keg and another almost full for the same amount of time and effort.

This has been so consistent for me that I haven't brewed any other way than this for at least ten brews.

I have recently changed to a fabricated 400 micron SS basket instead of a bag, but the recipes and results are initially the same.

 

[wepeeler]

Interesting thread. I've done about 10 5 gallon BIAB batches, and my BH efficiency is usually right around 72%. I did my first 11 gallon batch the other night and way undershot my efficiency - I ended up with 79%. My OG was 1.065 instead of 1.059. I'm certainly not complaining, as I wanted the beer to be 6% not 5%, but I'll have to do another 11 gallon batch soon to see if the 79% is consistent. I started with less grain than I really wanted to, simply because I was afraid of overflow while mashing. I had about an inch of room to the top of the kettle with 12 gallons of mash water and 25 pounds of grain.

 

[NitrogenWidget]

I came in under again with a 10 gallon batch but I noticed after I started the mash that my corona mill gap wing nuts were loose so I wasn’t getting the crush I needed. So I boiled it down to 9 gallons in order to hit an OG I could live with. Since my buttering hops were 3.9 and the only ones it won’t throw it out of whack. Next week will do a 5 gal batch and see what happens

 

[PersonalBrewer]

Interesting thread.........My OG was 1.065 instead of 1.059. I'm certainly not complaining, as I wanted the beer to be 6% not 5%, but I'll have to do another 11 gallon batch soon to see if the 79% is consistent. I started with less grain than I really wanted to, simply because I was afraid of overflow while mashing. I had about an inch of room to the top of the kettle with 12 gallons of mash water and 25 pounds of grain.

Very interesting. I started adding 10% more grains when going for 10 gals into two kegs gave me a bit low OG on the first or second batch. Talked with the best brewer I know at the LHBS, we theorized that the lower OG came from less water causing less conversion. I am getting higher OG numbers with the step infusions and have some room to play with trying less grains so I will give that a try and see how it turns out, and if my ABV does well also.

In all honesty I have never been concerned enough about efficiency to bother tracking or calculating. I just set my efficiency to 70% in Brewsmith and normally hit or exceed my OG predicted. However, when doing the 11.5 gal batches into the fermenters (10 or almost 10 into two kegs) numbers are not as consistent because you're u'm sing a 15 gal kettle. FWIW, my Northern Brewer 15 is actually about 15.5, and I'm mashing about 14/14.25 gallons. I have been using about 30lbs +/- of grains total.

Will try the next brew with a known recipe and use a bit less grains.

Won't be apples to apples because now doing infusion step mashes and wasn't doing that previously. It does however seem to hit a higher OG, and more fermentability.

 

[wepeeler]

Very interesting. I started adding 10% more grains when going for 10 gals into two kegs gave me a bit low OG on the first or second batch. Talked with the best brewer I know at the LHBS, we theorized that the lower OG came from less water causing less conversion. I am getting higher OG numbers with the step infusions and have some room to play with trying less grains so I will give that a try and see how it turns out, and if my ABV does well also.

In all honesty I have never been concerned enough about efficiency to bother tracking or calculating. I just set my efficiency to 70% in Brewsmith and normally hit or exceed my OG predicted. However, when doing the 11.5 gal batches into the fermenters (10 or almost 10 into two kegs) numbers are not as consistent because you're u'm sing a 15 gal kettle. FWIW, my Northern Brewer 15 is actually about 15.5, and I'm mashing about 14/14.25 gallons. I have been using about 30lbs +/- of grains total.

Will try the next brew with a known recipe and use a bit less grains.

Won't be apples to apples because now doing infusion step mashes and wasn't doing that previously. It does however seem to hit a higher OG, and more fermentability.

I'm not too concerned with efficiency, but I am with reproducibility, so I like to track my numbers. Honestly, the difference from 72% to 79% was a pound of grain on a small scale, so $2 is nothing. Obviously more of a concern for hundreds of gallons...but for what I need, I'm good with where I'm at. I just want to be able to consistently produce the same product over and over, so that's why I track. I was also told that efficiency lacks with more grain and less water. I wanted to top off my kettle with as little water as possible, so I started with less grain and more water than I initially wanted for the mash. That way if I overflowed, I could adjust my recipe. I just didn't want a 4% beer, so I tried to get right in the middle. Worked out, as I really wanted a 6% (which I should get close depending on the yeast), but would have settled for a 5%. So in the future, I think I can cram in MAYBE 5 more pounds of grain by stirring very slowly. Also, I guess I could shoot for a higher OG by starting with more grain and less water, but I think that's where I would see a bigger drop in efficiency. It's all experimentation at this point, so I'm learning on the fly. I'll keep track, and let you know when I hit the sweet spot. The real test will be when I attempt my first NEIPA 11 gallon batch.

 

[NitrogenWidget]

it happened again.
10 gal. batch, 26lbs of grain ended up with 1.042 og.
I discovered my corona mill set-up had loosened up a bit after i started the mash.
So my crush wasn't as fine as it usually is.

IDK.
I'm just going to boil it down until I get where I need to be OG. even if I end up with only 9 gallons.
i'm using 3.9% williamette for bittering so not worried.

 

[wilserbrewer]

I discovered my corona mill set-up had loosened up a bit after i started the mash.
So my crush wasn't as fine as it usually is.

.

The wing nuts on the corona mills are pretty crappy quality. I replaced mine w/ better ones from ace hardware that allow tightening w/ a pair of pliers, mill stays set where you want it.

 

[NitrogenWidget]

The wing nuts on the corona mills are pretty crappy quality. I replaced mine w/ better ones from ace hardware that allow tightening w/ a pair of pliers, mill stays set where you want it.

I followed your guide and added washers but kept the wing nuts, so yeah it's possible they were getting loose on me before and I didn't notice.
Could be the reason all my last few batches had horrible efficiency.
Because my crush wasn't as fine.

 

[wepeeler]

it happened again.
10 gal. batch, 26lbs of grain ended up with 1.042 og.
I discovered my corona mill set-up had loosened up a bit after i started the mash.
So my crush wasn't as fine as it usually is.

IDK.
I'm just going to boil it down until I get where I need to be OG. even if I end up with only 9 gallons.
i'm using 3.9% williamette for bittering so not worried.

What volume of water are you starting with? And do you top up kettle after the mash? Those 2 variables are more important to OG than just the crush.