Having problems with over attenuation!

[BrewinSoldier]

Hey guys and gals! Looking for a little input because I'm getting really tired of ALL my beers always over attenuating.

I had this problem on my grandfather and also on my 3 vessel setup. This happens no matter what yeast I use or what temperature i mash at.

Here is my process. I always build my recipes with online software(brewers friend) and always build my water from scratch using bru'n water and 100% RO water. I mash either 60 mins or 90 mins(when pilsner malt is involved) via an electric rims system. I then fly sparge at 168°F. I boil 60 or 90 mins for the same reason mentioned above. I chill through a copper CFC and then move into one of my stainless conicals via the brewhouse pump. This creates some oxygen and its splashing into the fermenter. I always use a yeast pitch calculator and pitch the proper amount of yeast. Before pitching yeast and once temp of wort is at pitching temps via my glycol chiller, I use an oxygenation stone with pure o2 and hit the wort with 60 seconds at 1lpm on the regulator. Then I toss in the yeast.

I have made sure my temps in the mash tun as well as the temps on my auber controller are dead on. I always check mash temps with a thermapen as well.

For example, I have two beers in the fermenter right now. I have a NEIPA that i just kegged tonight. It finished at 1.004 which is ridiculous. I've never had a NEIPA finish that low using 1318 yeast. Usually they finish low but more around the 1.008 mark. It was supposed to finish at 1.018(per brewers friend).

I also have a ballast point sculpin clone in a fermenter now. It was brewed on 6/25 and is already down to 1.008 using two packs of fresh wlp001. I did mash this one low at 149°F and actually did a mashout just to play around and see if it makes a difference. I don't usually do a mashout but have the capability very easily with my RIMS system. I just don't like to take the extra time to do it, but if it will help my way lower than calculated FG(1.014 via brewers friend) then I will start doing it.

Any ideas? Why am I ALWAYS way lower then the calculated FG on the calculator?

 

[doug293cz]

Since you are doing a fly sparge, you should be doing a mashout (raise mash temp to ~170°F) to stop the enzyme action. 168°F sparge water will not raise the grain bed temp fast enough for an effective mashout. 90 minute mashes may also be part of you problem.

Brew on

 

[bigdawg86]

This may be a silly question... but what is your method for checking gravity? Is your hydrometer calibrated? Is your temp of beer the calibrated temp for the hydrometer? I have never had a beer finish that low across many yeasts myself, even if I mash low, long, and add dextrose... so it seems odd that you are gettting such low numbers.

 

[Pkrd]

Check if water is around about 1.000

 

[thehaze]

I'm thinking a gravity measurement error or maybe a contamination problem? How do the beers taste? Have you let beers that over-attenuated to age for a few weeks, months? Did they turn bad or just slightly oxidized/faded in the aroma/flavour department? Have you had gushers ( only if you are bottling )?

Can we get the recipe for the NEIPA, that finished at 1.004 and a bit of the process? 1.008 is actually an OK FG for an IPA, so that's really not that strange. It depends where it started and you mashed low. Combine this with a fairly simple grain bill, and 001 would easily achieve over 80-82% attenuation.

Regarding calculators: know that they make predictions using generic data about grains and their diastatic power, yeast attenuation, mash. temp., efficiency, etc. They are not precise by any means, nor are they intended to be. At least, this is what I feel. I too use Brewer's Friend, and for me, it's a tool, helping me design the recipe and obtain an aprox. " image " of the beer, with an aprox. colour and ABV. This also applies to OG anf FG, as many things factor in.

Knowing your system, what each yeast can attenuate to, in different scenarios, what grain bills and mashing can achieve, can lead to results close to what a calculator predicts.

 

[BrewinSoldier]

Since you are doing a fly sparge, you should be doing a mashout (raise mash temp to ~170°F) to stop the enzyme action. 168°F sparge water will not raise the grain bed temp fast enough for an effective mashout. 90 minute mashes may also be part of you problem.

Brew on

Thanks for the info. I am definitely going to start doing them going forward. I did it with the Sculpin clone I brewed but it still dropped to 1.008, which is within reason for 001, but with 1318 1.004 is a little ridiculous, especially when I was aiming for 1.014 to leave a little residual sweetness being a NEIPA.

As for the 90 minute mashes, I only do that along with a 90 minute boil with pilsner malt to prevent DMS. Anything else gets 60 mins. I have been thinking about cutting my 60 min mash down to 45 mins lately to see what happens. I'm also thinking of trying a batch I don't add oxygen to with the wand, and only leaving the oxygenation I get from transferring to the fermenter.

This may be a silly question... but what is your method for checking gravity? Is your hydrometer calibrated? Is your temp of beer the calibrated temp for the hydrometer? I have never had a beer finish that low across many yeasts myself, even if I mash low, long, and add dextrose... so it seems odd that you are gettting such low numbers.

I use a Misco digital hydrometer that tests both dissolved solids and specific gravity at the 60/60 scale. It has built in temp correction and is dead on with my regular hydrometer at 60°. I calibrate it with distilled water before each use. My LHBS says being able to get that low of gravities is a blessing, but on beers where I don't want that it sucks.

Check if water is around about 1.000

Water is right at 1.000 from the RO machine.

 

[BrewinSoldier]

Would too much oxygen via my oxygen wand cause it to drop so low? I'm thinking about only letting it have whatever oxygen it gets from the transfer next time and not adding anymore via the wand to see if that is the reason why.

 

[ccous]

Mash out, as stated above. If you never get above 170F, those enzymes are working right up until the temp gets to that point during your boil.

 

[wobdee]

Would too much oxygen via my oxygen wand cause it to drop so low? I'm thinking about only letting it have whatever oxygen it gets from the transfer next time and not adding anymore via the wand to see if that is the reason why.

This is where I'd start looking. When I used pure O2 I occasionally had some over attenuation issues. There's no way of really knowing how much O2 is in your wort without an O2 meter.

I no longer oxygenate my wort, I oxygenate my yeast slurry in a jar with a little bit of wort and shake for about 30 sec, let it sit for about 30 min then pitch.

 

[doug293cz]

Thanks for the info. I am definitely going to start doing them going forward. I did it with the Sculpin clone I brewed but it still dropped to 1.008, which is within reason for 001, but with 1318 1.004 is a little ridiculous, especially when I was aiming for 1.014 to leave a little residual sweetness being a NEIPA.

As for the 90 minute mashes, I only do that along with a 90 minute boil with pilsner malt to prevent DMS. Anything else gets 60 mins. I have been thinking about cutting my 60 min mash down to 45 mins lately to see what happens. I'm also thinking of trying a batch I don't add oxygen to with the wand, and only leaving the oxygenation I get from transferring to the fermenter.

...

Mash time has no effect on DMS. DMS is created in the boil from SMM that thermally degrades. Below about 170°F, SMM degrades at a negligible rate, so essentially no DMS is created before the boil. It is important to cool from boiling to ~170°F quickly so that creation of DMS is minimized after flameout, when DMS will not volatilize nearly as fast as when boiling. After a 60 minute boil about 1/4 of the original SMM is still in the wort. After a 90 minute boil it's down to about 1/8 of the original.

Would too much oxygen via my oxygen wand cause it to drop so low? I'm thinking about only letting it have whatever oxygen it gets from the transfer next time and not adding anymore via the wand to see if that is the reason why.

Over attenuation is the result of not having enough unfermentable sugar in the wort. I don't think over oxygenation will cause over attenuation, but it may be bad for yeast health.

Brew on

 

[dmtaylor]

You're mashing too long. I've been mashing for just 40-45 minutes every batch for the past 11 years. You might benefit from something like this.

DMS will not be a problem for you in the 21st century. Mash doesn't affect it, and boil time also does NOT need to be extended for homebrewers. Only if you actually detect DMS in your beers do you need to adjust. But vast majority of homebrewers never have this problem.

Look -- your brew day just got about an hour shorter. Less time brewing and more time drinking!

 

[BrewZer]

Not an all-grain guy, but I consistently get FGs much lower than predicted. The one thing I've identified is fermentation temperature being at the upper range of acceptable temps since I don't have a fermentation cooler.

I'm going to assume you watch the fermenter temps as closely as you watch your mash, but maybe your temps are sneaking up on you...?

 

[BrewinSoldier]

Not an all-grain guy, but I consistently get FGs much lower than predicted. The one thing I've identified is fermentation temperature being at the upper range of acceptable temps since I don't have a fermentation cooler.

I'm going to assume you watch the fermenter temps as closely as you watch your mash, but maybe your temps are sneaking up on you...?

Yeah I have 3 stainless conicals all connected to a glycol chiller with pumps and two temp gauges per conical. They hold within .5 degrees of where I have them set. I will usually start at around 66° for the first couple days, then bump to 68° for the remainder of fermentation. Then a few days diacetyl rest at 70°, then cold crash a few days and add gelatin. Then into the keg via co2 pressure transfer and intoa 37°F keezer.

 

[BrewinSoldier]

I didn't q

You're mashing too long. I've been mashing for just 40-45 minutes every batch for the past 11 years. You might benefit from something like this.

DMS will not be a problem for you in the 21st century. Mash doesn't affect it, and boil time also does NOT need to be extended for homebrewers. Only if you actually detect DMS in your beers do you need to adjust. But vast majority of homebrewers never have this problem.

Look -- your brew day just got about an hour shorter. Less time brewing and more time drinking!

I do quite a few lagers and pilsners. Everything I've read says if you don't do a 90 minute boil with pilsners malt, that you will have DMS. I guess I've always played it safe but I've made a few award winning pilsners so I guess it's working out. I use floor malted pilsner malt and use a multi step mash which usually takes a little longer. I don't mind when these finish on the drier side because that's what I want, but for a NEIPA I just can't get them to stop at the 1.014 mark. I do have the option to drop the yeast out with a cold crash and try to dump most of them, but I know there will still be some left. And then I screw myself out of the dry hopping at the 70° mark. I feel like they don't stay in suspension long at all if I was to try it at 34°.

Sounds like I have a few things to try on the next brew though. I'll try a shorter mash(45mins) as long as it's clear. I'll also try not using the oxygen wand just to see what happens.

I'm curious how people are mashing at 149-150° for a NEIPA and still getting to 1.014 with 1318 yeast?

Shorter brew days are always great..and mine seem to take FOREVER with cleaning. I try to build my water profiles and measure out all the minerals a few days before to save time.

 

[Bryggeri]

Just my 2 cents.
If you are hitting regularly low numbers, you ferment out completely (no bottle bombs if you bottle of your keg)
My personal experience, conversion of the majority of the sugars is in the early mash, say first 20 minutes, if you are on the higher side more long chain sugars, on the low side more short chain. like wise the longer the enzymes interact the long chains they are broken into shorter chain sugars. Likewise you can mash longer to get more fermentables (allow enzymes to react longer breaking sugar chains down).
So i would recommend setting your targets on a higher on strike and initial mash-in temp and try to minimize any swing below your target mash temp in the early part of mash.
This is what I needed to consider when I was in a similar situation

 

[Amadeo38]

So i would recommend setting your targets on a higher on strike and initial mash-in temp and try to minimize any swing below your target mash temp in the early part of mash.

I second this thought. Although it doesn’t really answer why others can mash at the same temp as you and use the same yeast but get lower attenuation. It’s more of a compensation technique for whatever is going on with your system.

I was under the impression that there is an upper threshold for the ppm of o2 that can dissolve into a liquid. I wouldn’t worry that you’re “over-oxygenating.”

You never answered the question someone else asked, but I assume your beers aren’t going sour with time or gushing from the bottle, when/if you bottle? Would you say your attenuation is trending toward drier and drier beers with each successive brew? Often times when gravity continues to drop below expectation, there’s an infection in the brewhouse.

 

[BrewinSoldier]

Just my 2 cents.
If you are hitting regularly low numbers, you ferment out completely (no bottle bombs if you bottle of your keg)
My personal experience, conversion of the majority of the sugars is in the early mash, say first 20 minutes, if you are on the higher side more long chain sugars, on the low side more short chain. like wise the longer the enzymes interact the long chains they are broken into shorter chain sugars. Likewise you can mash longer to get more fermentables (allow enzymes to react longer breaking sugar chains down).
So i would recommend setting your targets on a higher on strike and initial mash-in temp and try to minimize any swing below your target mash temp in the early part of mash.
This is what I needed to consider when I was in a similar situation

I always use my blichmann bottle filler for filling bottles off the keg, and I usually use it to fill cans. Sometimes I get lazy and if I know the beer will be drank in the next few days, I'll fill the cans right from my taps with the perlick growler filler tube. The only time I bottle is for submitting to BJCP comps.

As for the mashing in temps, I USUALLY use a calculator and even measure the temp of my grains to calculate the mash in temp. I am always pretty dead on. When I get lazy and guess, it will drop a little lower but with my RIMS system it bumps the temp right back to my mash temp within a minute or two. I think one problem with my mash is that I wait until it is really clear. I will keep an eye on it next time and probably mash out as soon as I see starch conversion is complete via an iodine test.

 

[BrewinSoldier]

I second this thought. Although it doesn’t really answer why others can mash at the same temp as you and use the same yeast but get lower attenuation. It’s more of a compensation technique for whatever is going on with your system.

I was under the impression that there is an upper threshold for the ppm of o2 that can dissolve into a liquid. I wouldn’t worry that you’re “over-oxygenating.”

You never answered the question someone else asked, but I assume your beers aren’t going sour with time or gushing from the bottle, when/if you bottle? Would you say your attenuation is trending toward drier and drier beers with each successive brew? Often times when gravity continues to drop below expectation, there’s an infection in the brewhouse.

I'm definitely going to have to play around with some stuff. To throw another wrench in, I just got my new 30 gallon spike kettle that now I'm going to have to refigure all my brewhouse calculations again.

I think I brewed one batch of extract when I first started brewing, then 2 biab batches, then went straight to all grain. I've almost always had pretty low final gravities in all of my systems. Knock on wood but I've never had an infection. My beers always finish on the drier side which sometimes makes them a little bodyless.

 

[BrewinSoldier]

So a quick update on this.

I tried a few of the things you guys suggested on a brew I did 3 days ago. It was a West coast IPA that started at 1.058. it was calculated to finish at 1.014 again. I didn't oxygenate at all this time ither than naturally with transferring the chilled wort from the kettle to the fermenter. It's already down to 1.008.

I changed up the mash and did a mash out at 168° for 10 minutes, as well as tried a batch sparge for the first time. I pitched to packs of 1056 that were just over a month old(no starter) and the yeast calculator even said I was under pitching with that.

The only things I have left to rule out now are doing a shorter mash, and maybe bumping up my mash temp a few degrees(maybe 152). I just bought beer Smith 3 so I need to figure out how to use it and see how the calculations differ from brewersfriend.

If these don't fix my problem, I have no idea where to go next.

I also have a new 30 gallon mash tun in the way and am going to try no sparge mashing to see if that helps. It will definitely cut down on my brew day if anything.

 

[ccous]

168 isn’t all that high for a mash out. You’re still getting activity all the while you’re collecting wort. Get over 170, and truly get everything in that tun over that temp to denature enzymes. There are people doing their mashes at temps in the upper 160s, so that’s definitely not high enough to kill activity.

 

[BrewinSoldier]

168 isn’t all that high for a mash out. You’re still getting activity all the while you’re collecting wort. Get over 170, and truly get everything in that tun over that temp to denature enzymes. There are people doing their mashes at temps in the upper 160s, so that’s definitely not high enough to kill activity.

I have a 220v RIMS system so it's pretty easy to adjust temp. What temp exactly should I mash out at to completely stop the process?

 

[doug293cz]

I have a 220v RIMS system so it's pretty easy to adjust temp. What temp exactly should I mash out at to completely stop the process?

Since you are using Bru'nWater to build the water profile, your pH should be low enough that you don't have to worry about tannins at any mashout temp. Might as well heat it up to 175° - 180°F at the fastest rate your RIMS will go. This will stop the enzyme activity as quickly as your system can.

Brew on

 

[dmtaylor]

I have a 220v RIMS system so it's pretty easy to adjust temp. What temp exactly should I mash out at to completely stop the process?

Hot. Almost a boil. THAT will kill activity.

You need to shorten your total mash time to under 40 minutes. I swear that's going to help more than anything else.

Also I wonder........ have you ever used Wyeast 3711 or Belle Saison yeast? Possible you might have a permanent diastaticus yeast contamination someplace?

 

[BrewinSoldier]

Hot. Almost a boil. THAT will kill activity.

You need to shorten your total mash time to under 40 minutes. I swear that's going to help more than anything else.

Also I wonder........ have you ever used Wyeast 3711 or Belle Saison yeast? Possible you might have a permanent diastaticus yeast contamination someplace?

I've never used either of those. I've only used lager yeasts, 1056/001, 1318, Conan and a few other regular IPA or ale yeasts. I'm working on getting some Acid #5 to use to run though all my conicals and kettles(having a really hard time finding it though). My IPA I mentioned above with 1056 yeast ended up finishing at 1.006. I did mash at 149° but even at that the calculator said it should finish at 1.012 or 1.011(can't remember which now).

I'll be brewing Thursday on my new 1/2BBL system so we will see what happens. It's a pilsner and I'll be mashing low around 150° I believe. I'll be doing a vanilla blonde shortly after that so I'll try the shorter mash on that one or maybe the Julius clone I'll be brewing soon.

 

[isomerization]

Why are you continuing to mash at 149F? You should repeat a recent recipe (as close as possible) and mash at 156F. Your FG should be 5-10 points higher.

I’m interested to hear whether the higher mashout step helps as well. I quit mashing out about 2 years ago and don’t have any FG issues. Just go straight from the mash to boiling (adding a batch sparge to the kettle if recipe size calls for it). It was always counterintuitive to me that higher temps, which promote formation of longer chain fermentables (right?), would result in more attenuative wort. What do BIAB people do?