I've missed my numbers twice in a row... Why?

[carrsgarage]

It's been about two years since I brewed last and I finally got my 3V HERMS set back up after a move.
I brewed three weeks ago and it went very poorly. I overshot my mash temperature by 20⁰, had a boilover, and ended up with a really sad end product after a week's worth of fermentation.
The O.G. should have been 1.066, but I ended up with 1.053. F.G. ended up being 1.021. it's the first batch of beer that I've ever dumped instead of kegged.
I brewed the same recipe again this morning, figuring I had all the bugs worked out. The brew process went absolutely wonderfully, compared to the last attempt. However, I still missed my numbers. This time around, the O.G. is 1.050.
Since I overshot the mash temp so badly the last time around, I started with a cooler strike water - 168⁰ instead of 178⁰ and had to bring the mash temp up from 155⁰ to 158⁰ after under-letting the grist, which took about 15 minutes. I then mashed for 45 minutes exactly at 158⁰. I checked for starch conversion using iodine and I was good to go.
I fly sparged using a Blichmann Auto-Sparge which may not have been set to exactly the right height, but worked fine - no stuck sparge or anything like that.
I'm really not sure how I missed my O.G. this time around. I have never been off by this much before.

Any thoughts?

 

[Jag75]

Try starting at a lower mash temp , then step up . Or mash at 152 - 153 for the entire mash.

 

[carrsgarage]

Try starting at a lower mash temp , then step up . Or mash at 152 - 153 for the entire mash.

That's what's so surprising, my initial mash temp was about 155⁰ today. The last time around, it was well over that for the duration of the mash - strike at 178⁰ and the mash stayed between 165⁰ and 175⁰ and I ended up with an O.G. better than today's brew.

Could the age of my grain have anything to do with it?

 

[doug293cz]

I suspect the grain crush you have now is coarser than what you got when you brewed in the past. Larger grits take longer to gelatinize, which must happen before conversion can be completed. That combined with a short (45 minute) mash could lead to low conversion efficiency. And since mash efficiency = conversion efficiency * lauter efficiency, low conversion efficiency leads to low mash (and brewhouse efficiency.)

When you did the iodine test, did you include some grain bits, and crush them up to release any starch they might still contain? Sampling just the liquid can lead to erroneously negative starch tests.

A better way to check for mash completeness is to test the SG of the wort in the mash. The max SG, at 100% conversion, depends almost entirely on mash thickness (qt/lb, or L/kg.) The wort must be well homogenized prior to taking an SG sample. The table below shows maximum possible mash wort SG for a typical grain bill (~80% extract potential, dry basis.) If your SG is significantly below the table value for your mash thickness, then you should mash longer.

Brew on

 

[carrsgarage]

I haven't changed my mill settings at all - same crush as I was doing before.

 

[hotbeer]

Don't confuse a higher OG as being a better thing without considering other things. Your wort has both fermentable and unfermentable sugars in it. Both contribute to the SG value you are getting for your OG.

Your higher mash temps that you had might well have given you a higher SG but there very well may be more unfermentable sugars that will have your FG being a higher SG too.

 

[BrewerofBeers]

It's been about two years since I brewed last

When's the last time you bought grain? If it's been a while, or hard to explain, just know that old grain can sadly produce a reduced efficiency, and that's the truth.

 

[carrsgarage]

When's the last time you bought grain? If it's been a while, or hard to explain, just know that old grain can sadly produce a reduced efficiency, and that's the truth.

My grain is... well... a little old. It's probably about two and a half years old at this point; maybe even three. I bought a sack and put it in a Vittles Vault, expecting to use it in rather short order. Then we moved.
I had my doubts about it, but it looked, smelled, and tasted fine, so I figured why not.
My gut told me it was old grain causing my issues, but I didn't want to believe it.

 

[carrsgarage]

Don't confuse a higher OG as being a better thing without considering other things. Your wort has both fermentable and unfermentable sugars in it. Both contribute to the SG value you are getting for your OG.

Your higher mash temps that you had might well have given you a higher SG but there very well may be more unfermentable sugars that will have your FG being a higher SG too.

I definitely think this was the issue with my first batch. It was fermenting a long with no problem at all when it just hit a wall at 1.022 and stopped dead. I figured I had gotten a bunch of unfermentable sugars from my high mash temp.
It's going to be interesting to see where today's batch finishes.

 

[day_trippr]

My grain is... well... a little old. It's probably about two and a half years old at this point; maybe even three.

fwiw, I have been brewing with base malts I bought in 2020 with no apparent deviation from expected gravities using the same recipes I used in 2019. I'd be inclined to look elsewhere for mysterious extract and/or efficiency losses...

Cheers!

 

[RogerGrahl]

Carrsgarage, this is a long shot, but is there any chance of measurement or profile error? This is a fairly large miss, but that should at least make it easier to find the causes. Good luck. Let us know what you find. Brew on….

 

[Bobby_M]

Are you just mashing for 60 minutes without taking any intermediate gravity readings? If I'm coming short of my known conversion efficiency, I'll extend the mash, ramp the temp a bit, stir, whatever it takes. Sometimes it just doesn't move but that's usually an odd case.

 

[hotbeer]

For a future brew, a iodine test might also be useful during your mash. I think but don't know, that you can have a decent OG, but it just be starches that haven't converted to sugar.

If you do one, then do one very soon after you begin the mash so you'll know what it looks like before the conversion takes place. Then you won't be as unsure of what you see on the later test or tests.

 

[user 338926]

There's loads of software to calculate the water temps so your mash ends up at the correct temp. Lots of free sites, etc. Input the grain weight, tun weight, water amount and it'll tell you what temp is should be to hit the proper mash temp. Typically 160-170, but never any higher. If you had one start at 178, all the enzyme was stopped before you started. No wonder it didn't ferment. It wasn't sugar. You can't go high and back down low, it has to start low and then raise through the various enzyme activity ranges. Look up step mashing and it'll tell you where those enzymes stop working, just for future reference. Everything is stopped above 168F.

 

[carrsgarage]

Here’s a quick update for anyone following along (also, thanks for all the tips and insight):

Saturday’s brew day really went well in retrospect. I had fermentation activity by early evening (maybe 6hours after pitching) and darn good fermentation up until yesterday morning. When I got home from work, I checked on it and there were no more bubbles - it’s like it hit a brick wall. I’ve got a Tilt hydrometer in the fermenter and it’s reading 1.017.
So, my first batch went from 1.053 to 1.020 and my second batch appears to have gone from 1.050 to 1.017 - exactly the same attenuation.
I am really stumped here. I never would have expected the same results from what I would consider entirely different mashes/boils.
The ingredients were all the same.

 

[user 338926]

I battled "underattenuation" for years, all while brewing lots of very good beers. I've begun to wonder if maybe it wasn't my test equipment (Hydrometer/refractometer), my ignorance with using said tools, or any number of things. Most especially I've considered water chemistry, I mean there's got to be some common denominator as to why I had results that mirror yours. And also, why is that same phenomenon so common? You can read about that here 100x a day.

I use Bru'nWater and have for countless years. I haul water from work (town has nationally award winning fantastic water) in 15 gallon barrels which I load on my pickup w/forklift and take off by hand. That water per lab test, is within 7ppm of RO in every aspect. I calibrate my pH meter w/buffer solutions, calibrate thermometers and use multiple thermometers as X references, I mean, what could I be missing?

I harvest yeast, especially when the yeast cake/trub looks beautiful and clean. I will say this, when I have a yeast cake that performs really well, the children of that yeast cake perform quite similarly. Is there an anecdotal circumstance there? I think it's above my pay grade to answer that.

I've even considered buying a high end microscope to look at yeast'ies, not that I have any clue what I'd be looking for. But I bet I could waste even more money chasing this problem., assuming of course that there's really a problem to chase. I just ruined n dumped a batch of Blind Pig (10G) chasing a problem that only later when it was too late, did I discover there never was an issue to begin with. Heartbreaking... Most expensive beer I tried since getting back into brewing earlier this year. By a long shot...

 

[tracer bullet]

Try starting at a lower mash temp , then step up . Or mash at 152 - 153 for the entire mash.

Agreed! Worth repeating.

If you did a good crush (it need not be the same as in the past, just be sure it's good, typical recommendation is .030" gap or "credit card" thickness gap to start with), and mash in the low 150's or even at 150F, and do so at least an hour but go for maybe 1.5 hours (with some stirring or recirculation), you'll have a fermentable wort. Assuming it's not a strange recipe that barely converts.

I'd try again with those ideas in mind.

 

[user 338926]

Just curious, maybe I missed it above, but what type of mash vessel are you using?

 

[carrsgarage]

Just curious, maybe I missed it above, but what type of mash vessel are you using?

I'm using a 15 gallon stainless steel pot, cycling the wort through a HERMS coil for the duration of the mash. The HERMS coil is mounted in another 15 gallon pot that I kept at a constant temperature (3 degrees warmer than the desired mash temperature) on the second brew attempt.

 

[hotbeer]

It's only four days later. It might go a little lower. But it also might be finished. Finished as far as fermentation goes, but there are other reasons to leave in in the FV much longer.

I'm not certain you've said what you are brewing. My porters that I've been doing recently have been finishing at a higher FG than all the other pales ales and IPA's I previously brewed. I'm thinking it might have to do with pH of the wort. However I don't have anything to check with accurately and have been making minor adjustments to my water to see what happens between each batch.

And how well did you hold your mash temp this last time?
So if your desired temp was 155°F and you are 3 degrees higher, then you are still 4 degrees hotter than I mash.

 

[user 338926]

Gotcha. Sorry, I missed the HERMS comment in line one of the OP... Would have answered my question before I asked it. I'm out of ideas for the moment, but I'll be following the discussion since it sort of applies to me as well.

 

[bailey mountain brewer]

What are you using to predict your OG ? Are your volumes coming out where they should be or do you have more wort then predicted? I agree with the above, mash in at a lower temp and let it come up. I mash 150 to 153 most of the time, then mash out.

 

[carrsgarage]

I guess knowing the recipe might help. I'm attempting to brew Revvy's Leffe clone. I used BeerSmith to adjust the recipe for my equipment. The results of the adjustments are as follows:

10 lbs. 12.5 oz. Pilsner (81.6%)
1 lb. 1.6 oz. Munich Malt (8.3%)
5.8 oz. Biscuit Malt (2.8%)
3.9 oz. Melanoiden Malt (1.8%)
1.51 oz. Styrian Holdings at 60 min.
0.79 oz. Saaz at 30 min.
11.6 oz. Table Sugar at 15 min.

Mash with 16.21 quarts of water at 158⁰ for 45min. per recipe.
Fly sparge with 168⁰ water to achieve pre-boil volume of 8.17 gallons.
Boil for 60 minutes.

I'm using a refractometer, a traditional hydrometer, and a Tilt hydrometer to check gravities. Obviously, I'm not using the Tilt to check my pre-boil gravity, but all three are in agreement on the gravity.

 

[hotbeer]

I put that info in the recipe software I use, and it shows the predicted FG using US-04 as being.... 1.013 when adjusting the efficiency to get your stated OG of 1.050. And assuming this was ending with 5 gallons after the boil, though suspect yours was more.

So you aren't that many points off if 1.017 does turn out to be the FG.

Admittedly there might be some errors in this. I changed PC's recently and this is a new install of this software on it that I haven't tailored to my stuff yet.

 

[tracer bullet]

And assuming this was ending with 5 gallons after the boil

Another good point. I went back to look for volume, and see 8.17 gallons pre-boil. That's far more than I'm used to seeing, I think most would say the same. What's the final volume at the end of boil? If it's still high (6 full gallons, maybe more?) then the 1.050-ish isn't far off at all. It's basically diluted compared to what most of us would deal with on a "5 gallon" brew.

I think we might have all assumed you started with a boil volume of maybe 6.5 gallons and got it down to like 5.5 gallons, with 5 - 5.25 going into the fermenter. Not exactly that but something like it. But 12 lbs of grain ending with 6 or more gallons probably could easily be at 1.050 and it mean that nothing went wrong at all and there's nothing to fix? Except perhaps using less water next time...

 

[carrsgarage]

I calculated the pre-boil volume needed based on how much gets left behind in the brew kettle, my counterflow chiller, and my fermenter so that Im guaranteed to have plenty to fill a 5 gallon keg (I'm greedy and want it full LOL).
According to BeerSmith, my pre-boil gravity should have been 1.051, but mine was 1.035. Estimated post-boil gravity should have been 1.066. This should have given me 5.5 gallons in the fermenter and 5 gallons final volume.

 

[day_trippr]

Mashing at 158°F on a herms rig is fraught with danger if the differential between the hex and the mlt is more than a couple of degrees. Even then it is likely circulating the saccharification enzymes to an early demise - at the very least pushing the yield towards dextrins. I would definitely recommend working the other end of the temperature range at least until whatever issue is at play is resolved. Maybe even try a Hochkurz temperature profile...

Cheers!

 

[Deadalus]

How fast did you sparge? An autosparge just prevents inputting too much water but you set the outflow rate.

How well calibrated is your Tilt? It sounds like you have relied on your reading of 1.017 per the Tilt? Did you do that with that with the first batch, that is, use the Tilt as the final reading. Did you look at your Tilt graph to see if it was leveling out at the end? I just recalibrated mine but only to distilled water as I didn't have enough sugar in the house that day to do a multipoint calibration. It ended up being 2 points off from my hydrometer (tilt was lower) and as it is finishing up this latest batch, seems to be a couple of points too high on FG.

 

[Deadalus]

Mashing at 158°F on a herms rig is fraught with danger if the differential between the hex and the mlt is more than a couple of degrees. Even then it is likely circulating the saccharification enzymes to an early demise - at the very least pushing the yield towards dextrins. I would definitely recommend working the other end of the temperature range at least until whatever issue is at play is resolved. Maybe even try a Hochkurz temperature profile...

Cheers!

I typically mash no higher than 156 and I also worry about this myself. It's more of a "is the temperature reading accurate". I have a 3V EHERMS. @carrsgarage are you using a PID(s)? They can drift and need to be calibrated with a calibrated thermometer. In the past, I've had issues getting mine dialed in.

 

[mac_1103]

I calculated the pre-boil volume needed based on how much gets left behind in the brew kettle, my counterflow chiller, and my fermenter so that Im guaranteed to have plenty to fill a 5 gallon keg (I'm greedy and want it full LOL).

Wait a second... isn't most of "what's left behind" in all of those places wort? So aren't you simply diluting your wort when you account for all of that by increasing the amount of water without increasing the amount of grain? Or am I misunderstanding something about your calculations?

 

[hotbeer]

Estimated post-boil gravity should have been 1.066. This should have given me 5.5 gallons in the fermenter and 5 gallons final volume.

Before I made the efficiency corrections for the OG you came up with, I also was showing about 1.065 or maybe a tad lower than that. I was surprised that the predicted FG was 1.017 with S-04. Which is the current SG that you reported. But of course I don't know if we are considering this your FG yet since it's only day 4.

Did you ever say what yeast you used?

Still, I'm thinking your main issue is the high mash temps. Though only because I've never used temps quite that high except for brief excursions that get corrected quickly.

Though still I wonder if the pH might be a factor too. But someone that knows more about pH and it effect on yeast fermentation of beer will have to address that.

But don't take any of this as me being an expert or anything beer. I only state these because I've brewed beer and these are the constructs I've made for myself based on what I've read and so far have done.

 

[mac_1103]

According to BeerSmith, my pre-boil gravity should have been 1.051, but mine was 1.035.

FWIW, Brewer's Friend says that grain bill in that volume should have a pre-boil gravity of 1.042.

 

[user 338926]

Wait a second... isn't most of "what's left behind" in all of those places wort? So aren't you simply diluting your wort when you account for all of that by increasing the amount of water without increasing the amount of grain? Or am I misunderstanding something about your calculations?

Just doing back of the napkin math on his recipe in post-23, but he's got just about 13 lb of malt for this eventual 5 gallon recipe. That's a pretty hefty grain bill, so I suppose that's what he means by accounting for all that loss. I just did a 13 lb 10 gallon recipe that started at 1.044. But I agree, the numbers are very strange here.

 

[mac_1103]

Just doing back of the napkin math on his recipe in post-23, but he's got just about 13 lb of malt for this eventual 5 gallon recipe.

Yeah, but it really doesn't matter does it? If the difference between pre-boil volume and post-boil volume includes wort left in kettle as opposed to just water boiled off, then he's not going to hit his OG.

 

[mac_1103]

Just doing back of the napkin math on his recipe

Just as an aside, why doesn't anybody do math on the front of the napkin? Asking for Steven Wright.

 

[user 338926]

Yeah, but it really doesn't matter does it? If the difference between pre-boil volume and post-boil volume includes wort left in kettle as opposed to just water boiled off, then he's not going to hit his OG.

I'm not totally understanding this either . Maybe what he's trying to accomplish is to have super clear wort going into the fermenter. And he's willing to let all the solids collect in the bottom of the kettle before he moves it to the fermenter and just throw that stuff away. Even though it's gallons. And understanding that, he's adding more water and more grain so he can do that.

The number he's trying to hit isn't that high if he was actually trying to get all the sugar out of that 13 lb of malt. He's just missing what he's expecting and not understanding why. I'd be curious to know why all this wort is just thrown away, but I try not to question stuff when people are experimenting because quite frankly, I do some crazy experiments myself.

 

[user 338926]

Just as an aside, why doesn't anybody do math on the front of the napkin? Asking for Steven Wright.

Well, because if you're doing it with a ballpoint pen, it won't write anywhere that there's spaghetti sauce on the front.

 

[day_trippr]

lol! Back in the day establishments printed their moniker 'n' stuff on the "front"...

Cheers!

 

[carrsgarage]

Yes, "what's left" is wort.
I whirlpool at the end of the boil and try not to get greedy when pulling the wort out of the boil kettle so I don't get a lot of crap in the fermenter.
My counterflow chiller is 20' long plus the hoses that connect the pump to the chiller and the chiller to the fermenter.
I've also tried to get 5.5 gallons of wort into the fermenter so I can leave enough beer on the lees when transferring to the keg that I don't end up with a bunch of junk in the keg.

Maybe I'm overcompensating.
Maybe I worry too much.
What kills me is that I've never missed my O.G. by so much before.

 

[carrsgarage]

Also, the yeast I used is SafAle BE-256.