Challenging Brewday, Exhausted...

[jmitchell3]

Firstly, this is not an April fools post, this actually happened today and it seems the joke may be on me...

So my buddy and i from the homebrew club got together "borrowed" components for a big brew day today. Big beer, 52.5 lbs of grain for 15 gals preboil, targeting preboil gravity of 1.089 at 70% efficiency using a fly sparge.

Long story short, we doughed in our 2.5 brown bags of grain, hit our initial mash temp within 1.5F, hit our pH perfectly at +45 mins (remaining in 60 min mash), and commenced with refract readings from samples at 30 mins. 1.042. Then 1.054 at 15 mins. At this point we are thinking WTF. Did a conversion test with iodine, it indicated full conversion.

Started to runoff first runnings, just over 1.060. What is going on?!? We are thinking. Upon completion of fly sparging for 45+ mins we are still at 1.056 blended runnings. We have already begun heating the mash, try recirculating the hot wort (176F or so) back through the tun as a batch sparge. Did that for 30+ mins thinking maybe we could pick up additional sugars, and nada. Even added another gallon of fresh water to try and get something happening.

Collected 16 gals at 1.057 OG, representing an unbelievably low 48%. I couldnt try to mess up a mash and get 48% efficiency!!!

We started going over our figures as the boil commenced trying to find where we went wrong. We found nothing after triple checking our calculations, objective observations, etc. (Note: We are both relatively moderate to advanced homebrewers, with many many all grain batches under our belts. This was our first collaboration brew.)

We decided to go a bit further, and after draining all residual wort from the mash tun, we scooped out and weighed our spent grain. Assuming a mash grain absoprtion of .12 gallons per lb of grain, we estimated we should have pulled almost 100 lbs of spent grist from the tun (52.5 lb of grain * .12 * 8.33 lb per gallon plus our original grist weight...). The weight of the grist pulled from the tun was just over 66 lb leaving an estimated 36 lb of grist + water unaccounted for. That would, apparently, mean we may have been up to 18 lbs short of our paid-for 52.5 lbs of grain, which, to us, is unbelievable and suggests our lhbs operator may have shorted us almost 40% of our grain bill.

After an insanely exhausting 9 hour brew session, I would be grateful if anyone could help figure out what went awry and if it is infact plausible based on the evidence that our lhbs really screwed the pooch.

Thank you!

 

[mongoose33]

Do you recall the mash being incredibly thin versus what you normally would expect?

 

[jmitchell3]

It was definitely not what id call thick. Est 1.1qt per lb. so it shouldve been thick. And it didnt fill the tun as much as i had anticipated.

 

[bigdaddybrew]

52.5 pounds at 1.1 qt/pound is 18.64 gallons of mash. What is the size of the mash tun? Did it seem appropriately full? Sounds like you got ripped off.

 

[jmitchell3]

Igloo marine cooler, not sure the size.

 

[micraftbeer]

Igloo marine cooler, not sure the size.

I didn't think through the math on your "weighing the spent grain" study, but you have to include the fact that you freed a lot of the grain mass by the mash process and that flowed out as wort into your boil pot. If you just took your 66 lbs of grain, soaked it in room temperature and weighed it, maybe your math would work. But your spent grain will weigh less than unspent grain (with both of them dry).

But what I was really thinking was when you said "marine cooler", was what kind of grain strainer you had on the bottom. I used a 5 gallon cooler with a nice false bottom for quite some time and was getting efficiencies around 70%. I upsized to a 10-gallon cooler with a bazooka screen and I then got conversion efficiencies in the 40-50%. Needless to say, I no longer mash in my 10-gallon with a bazooka screen.

 

[cyanmonkey]

I had this kind of brew day recently.

I built a keggle mash tun and wanted to max it out with almost 27lbs in a 5.5 gallon batch; fly sparge (typically batch sparge). Ended up with 58.5% efficiency. The best thing I could come up with was I had some channeling on my sparge. I'm going to try batch sparging next time and hopefully increase my efficiency. Beer still turned out awesome, though.

Also, take in account for lower efficiencies on higher gravity brews.

 

[ncsuwerewolf]

Did you crush or did the LHBS?

 

[cyanmonkey]

Did you crush or did the LHBS?

I did and I went a tad coarser to avoid stuck sparge and I had never used this system before so I had no idea what I was going to get out of it. I've been using a picnic cooler with a bazooka screen, so naturally I assumed I'd get better extraction.

I had wondered if I was shorted grain, as well, but I've never had an issue with them doing it before and I trust them.

 

[stevehaun]

Either you were shorted on the grain or your crush was horrible. I would vote for the first based on 48% efficiency.

 

[BrunDog]

I guess lesson learned! Plenty behind you and plenty more to come! Sorry it cost you the beer you wanted.

I mill my own now, but before when I had the LHBS crush, I would still weigh the crushed grains before doughing in.

 

[jmitchell3]

I didn't think through the math on your "weighing the spent grain" study, but you have to include the fact that you freed a lot of the grain mass by the mash process and that flowed out as wort into your boil pot. If you just took your 66 lbs of grain, soaked it in room temperature and weighed it, maybe your math would work. But your spent grain will weigh less than unspent grain (with both of them dry).



But what I was really thinking was when you said "marine cooler", was what kind of grain strainer you had on the bottom. I used a 5 gallon cooler with a nice false bottom for quite some time and was getting efficiencies around 70%. I upsized to a 10-gallon cooler with a bazooka screen and I then got conversion efficiencies in the 40-50%. Needless to say, I no longer mash in my 10-gallon with a bazooka screen.

Yeah I don't know what the "transferred" mass would be but I expect not 36 lbs worth.

It's PVC manifold in a large rectangular cooler.

 

[jmitchell3]

I had this kind of brew day recently.

I built a keggle mash tun and wanted to max it out with almost 27lbs in a 5.5 gallon batch; fly sparge (typically batch sparge). Ended up with 58.5% efficiency. The best thing I could come up with was I had some channeling on my sparge. I'm going to try batch sparging next time and hopefully increase my efficiency. Beer still turned out awesome, though.

Also, take in account for lower efficiencies on higher gravity brews.

All I can say is we did a fly sparge and then 2 additional batch sparges with heated and drained wort. 48% is crazy. If it was 58.5 I'd be disappointed but not confused. I have never not once brewed a HHH Gravity batch with less than mid 60s efficiency.

 

[jmitchell3]

Either you were shorted on the grain or your crush was horrible. I would vote for the first based on 48% efficiency.

Here's a high res pic of grain before dough-in:View attachment ImageUploadedByHome Brew1459617983.893256.jpg

We commented before hand that it looks like a pretty fine crush as there we plenty of shredded husks. (We had no problems with draining the kettle.) another issue is that we were to have 4 pounds of flaked oats...of which I saw none in the grain we handled.

 

[jmitchell3]

Well we talked to the lhbs and they are refilling our grain bill at no charge! So guess we are rebrewing this Friday. I'll report back on how it goes!

 

[beernutz]

Here's a high res pic of grain before dough-in:View attachment 348419

We commented before hand that it looks like a pretty fine crush as there we plenty of shredded husks. (We had no problems with draining the kettle.) another issue is that we were to have 4 pounds of flaked oats...of which I saw none in the grain we handled.

You'd think that with almost 8% of your grist made up of flaked oats you would be able to see some evidence of them in that picture but I don't. To me that is further evidence you got shorted by your lhbs but at least they are compensating you.

Since my brewday disasters are normally self-inflicted you can take comfort in the idea that yours was likely out of your control.

 

[Jimbodaman]

I've had problems fly sparging with a manifold in my rectangular cooler. Major channeling can occur unless it's "engineered" properly. Now I just batch sparge with the same manifold and I get much better, and easier efficiency. I was getting about 60% efficiency fly sparging and now I get about 72%.

 

[jmitchell3]

I've had problems fly sparging with a manifold in my rectangular cooler. Major channeling can occur unless it's "engineered" properly. Now I just batch sparge with the same manifold and I get much better, and easier efficiency. I was getting about 60% efficiency fly sparging and now I get about 72%.

Yeah we were just talking to another club member about it and we may just batch sparge it for the rebrew...

 

[kh54s10]

I can't tell for sure but, compared to my crush, the picture in a previous reply doesn't look very good to me. I do use a corona style mill so my husks get shredded. But still it doesn't look well milled to me.

Then again, it doesn't look bad enough to cause the terrible efficiency that you obtained.

 

[wapitiscat]

Collected 16 gals at 1.057

I'm assuming you went ahead and fermented it. It would be interesting to know what the target style was and then try to pigeon hole this beer you get from the low efficiency. I think there are "repercussions" from an overly thin mash but can't recall what that might bring to the party.

You could call it Lower 48 Ale or something. It might be good.

Todd

 

[doug293cz]

Yeah I don't know what the "transferred" mass would be but I expect not 36 lbs worth.

It's PVC manifold in a large rectangular cooler.

Grain wt lost to the wort can be calculated as Mash_Efficiency * Extract_Potential (in %). So, for 70% mash efficiency and 80% extract potential, the weight of grain transferred to the collected wort would be 0.70 * 0.80 = 0.56 or 56% of the original grain wt. You can't use that number with your apparent grain absorption to calculate the weight of the wet spent grain, as your real absorption is significantly higher than your apparent absorption, because some of the volume of your collected wort is due to sugar. It is possible to calculate the weight of the wet spent grain when batch sparging, but not when fly sparging. To do the calculations you need to know the wt of the grain bill, the extract potential, volume of water used, volume of wort collected, and SG of wort collected.

Brew on

 

[jmitchell3]

Grain wt lost to the wort can be calculated as Mash_Efficiency * Extract_Potential (in %). So, for 70% mash efficiency and 80% extract potential, the weight of grain transferred to the collected wort would be 0.70 * 0.80 = 0.56 or 56% of the original grain wt. You can't use that number with your apparent grain absorption to calculate the weight of the wet spent grain, as your real absorption is significantly higher than your apparent absorption, because some of the volume of your collected wort is due to sugar. It is possible to calculate the weight of the wet spent grain when batch sparging, but not when fly sparging. To do the calculations you need to know the wt of the grain bill, the extract potential, volume of water used, volume of wort collected, and SG of wort collected.



Brew on

Ah, ok that makes sense. So check my math:

22.5 gallons of water used, kettle volume pre boil was 16 gallons. So less than 16 gallons (1.057 SG) of the 22.5 made it into the kettle, because some portion of the kettle volume is made up of extracted sugars. For our purposes we'll ignore this fact and call the pre boil kettle volume 16 gallons.

This leaves 6.5 gallons in the mash tun made up of 1) grain absorption and 2) liquid in the tun dead space. We dumped everything, liquid included into out buckets for weighing after the mash. So we will call it good for a total figure. Thus, 6.5 gallons x 8.33 lb per gallon for water = 54.14 lbs. based on these volumes and observed SG we achieved a mash efficiency of 48.2%. Assuming an extract potential on the low side (this was a stout) of 70%, that gives us 33.7% of the weight of the grain that made it into the kettle, or 17.7 lbs. that leaves 52.5 - 17.7 = 34.8lb of grain left in the mash tun. Total wet grain and dead liquor remaining should have been then 54.14 + 34.8 = 88.94 lbs.

We had 66 lbs total remaining...

 

[doug293cz]

Ah, ok that makes sense. So check my math:

22.5 gallons of water used, kettle volume pre boil was 16 gallons. So less than 16 gallons (1.057 SG) of the 22.5 made it into the kettle, because some portion of the kettle volume is made up of extracted sugars. For our purposes we'll ignore this fact and call the pre boil kettle volume 16 gallons.

This leaves 6.5 gallons in the mash tun made up of 1) grain absorption and 2) liquid in the tun dead space. We dumped everything, liquid included into out buckets for weighing after the mash. So we will call it good for a total figure. Thus, 6.5 gallons x 8.33 lb per gallon for water = 54.14 lbs. based on these volumes and observed SG we achieved a mash efficiency of 48.2%. Assuming an extract potential on the low side (this was a stout) of 70%, that gives us 33.7% of the weight of the grain that made it into the kettle, or 17.7 lbs. that leaves 52.5 - 17.7 = 34.8lb of grain left in the mash tun. Total wet grain and dead liquor remaining should have been then 54.14 + 34.8 = 88.94 lbs.

We had 66 lbs total remaining...

If we assume your grain bill had a dry basis extract potential of 80.13% (1.037), and 4% moisture, then the "as is" extract potential is:

Total Potential Extract = 0.96 * 0.8013 * 52.5 lb = 40.38 lb​

You collected 16 gal of wort with an SG of 1.057. That wort weighs:

16 gal * 8.33 lb/gal * 1.057 = 140.88 lb​

1.057 SG is equivalent to 14.04˚Plato or 14.04 wt% sugar. Thus your collected wort is:

Weight Sugar in Wort = 0.1404 * 140.88 lb = 19.78
Weight Water in Wort = 0.8596 * 140.88 lb = 121.10 lb
Volume of Water in Wort = 121.10 lb / 8.33 lb/gal = 14.54 gal​

Thus you left almost 8 gal of your original 22.5 gal in the mash tun. Your mash efficiency would then have been:

Mash Efficiency = 19.78 lb / 40.38 lb = 0.4898 => ~49%​

Now the confusion sets in as you said this in your OP about your process:

"We decided to go a bit further, and after draining all residual wort from the mash tun, we scooped out and weighed our spent grain."​

Was the liquid drained added to the BK, and included in the 16 gal total? If not, then that liquid represents a significant amount of unaccounted for weight. Also, what was your strike water volume?

Brew on

 

[jmitchell3]

If we assume your grain bill had a dry basis extract potential of 80.13% (1.037), and 4% moisture, then the "as is" extract potential is:

Total Potential Extract = 0.96 * 0.8013 * 52.5 lb = 40.38 lb​

You collected 16 gal of wort with an SG of 1.057. That wort weighs:

16 gal * 8.33 lb/gal * 1.057 = 140.88 lb​

1.057 SG is equivalent to 14.04˚Plato or 14.04 wt% sugar. Thus your collected wort is:

Weight Sugar in Wort = 0.1404 * 140.88 lb = 19.78
Weight Water in Wort = 0.8596 * 140.88 lb = 121.10 lb
Volume of Water in Wort = 121.10 lb / 8.33 lb/gal = 14.54 gal​

Thus you left almost 8 gal of your original 22.5 gal in the mash tun. Your mash efficiency would then have been:

Mash Efficiency = 19.78 lb / 40.38 lb = 0.4898 => ~49%​

Now the confusion sets in as you said this in your OP about your process:

"We decided to go a bit further, and after draining all residual wort from the mash tun, we scooped out and weighed our spent grain."​

Was the liquid drained added to the BK, and included in the 16 gal total? If not, then that liquid represents a significant amount of unaccounted for weight. Also, what was your strike water volume?

Brew on

Yeah, it was probably more like 17-17.5 gals in the kettle. We boiled for 3 hours and had almost 13 gallons post boil. the Pre-Boil Gravity was 1.057.

There wasn't more than 1 qt of liquid left in the tun after the grain was removed, and the total water volume was not more than 23 gallons.

At any rate any of those calcs give us more weight remaining in the tun than we had by quite a margin.

 

[doug293cz]

Yeah, it was probably more like 17-17.5 gals in the kettle. We boiled for 3 hours and had almost 13 gallons post boil. the Pre-Boil Gravity was 1.057.

There wasn't more than 1 qt of liquid left in the tun after the grain was removed, and the total water volume was not more than 23 gallons.

At any rate any of those calcs give us more weight remaining in the tun than we had by quite a margin.

Ok, I got creative with my batch sparge mash simulator and "Goal Seek" (and maybe even performed some unnatural acts - no goats were harmed.) I know you fly sparged, but fly sparge simulation is too hard for mortals, so I used what I had. 3X batch sparge shouldn't be too far off from fly sparge in efficiency for this exercise.

To get a residual mash weight of 66 lbs, the starting grain bill needed to be about 36 lbs, to get something self consistent with your measurements. So, I suspect you are right about your grain weight being less than you were expecting.

Brew on

 

[jmitchell3]

Ok, I got creative with my batch sparge mash simulator and "Goal Seek" (and maybe even performed some unnatural acts - no goats were harmed.) I know you fly sparged, but fly sparge simulation is too hard for mortals, so I used what I had. 3X batch sparge shouldn't be too far off from fly sparge in efficiency for this exercise.



To get a residual mash weight of 66 lbs, the starting grain bill needed to be about 36 lbs, to get something self consistent with your measurements. So, I suspect you are right about your grain weight being less than you were expecting.



Brew on

Wow. Thats some fellow geek work there, props! Thanks for your mad math assistance!