every beer is under attenuated!

[sgraham602]

Just about every batch out of my last 10 batches has been extremely under attenuated. Not sure where I'm going wrong here. Fermentation temps are spot on. I might be lacking on oxygenation. would over pitching potentially cause this as well? Some of my starters have been a bit larger than what "mr. malty" specifies.

 

[grathan]

Can you give a few examples of what extreme means to you?

Certainly lack of oxygen is a culprit. What's your process?

How big are your starters? Over pitching can under attenuate, but probably not possible in a 2L flask.

I wouldn't eliminate ferm temps just yet.

How long do you ferment these before racking?

Do you use RO water? Yeast need calcium and zinc.

Are you reusing old yeast on multiple batches?

Are you an extract Brewer? What kind of extract?

 

[polvofiloso]

Possibly any of the above. Just yesterday I listened to an old episode of Brew Strong on the Brewing Network, which was entirely about attenuation. I suggest looking it up and giving it a listen, it had a ton of great info. It was like the second or third episode, from way back in 08 or 09.

 

[sgraham602]

i havent had a batch finish under 1.015 in a while. Most recently a mild that had an OG of 1.037.

Lately, my oxygenation process has been nada. For a while i was using an O2 tank, but it has been empty for too long and I have been shaking the carboy ever since then. I'm embarrassed to say that I;ve just been giving it a few shakes and thats it.

My starters are typically about 1-1.5 L, in batches ranging in OG from 1.37-1.066.

I use a chest freezer with the probe bubble wrapped to the side of my fermentor. holding everything at about 66 (occasionally free rising up to 70 towards the end of ferm). As for racking, I typically do a loooong primary. Normally 3 weeks or so, then into the keg.

The more i think about it, I think my neglect of oxygenation might be the problem.

Thanks!!!

 

[uatuba]

I don't buy that oxygenation is causing that much of an issue...if it's all grain, I would think the problem lies elsewhere.

 

[sgraham602]

It's all grain. Typically mashing between 152-156.

 

[The_Doctor]

Possible culprits:

1: A lot of yeast with not enough O2 can make them go dormant (drop) early. This is what I'd put my money on. Most of the yeast in your starter are likely not seeing a proper aerobic phase which would lead to an unhealthy fermentation.

2: Check the temp of the beer itself, it may be lower than you think. In the same vein, what temp are you pitching at? Yeast shock is possible. Or if you're using english strains they may just need rousing.

3: Check your latest water report, if you have very soft water it may be a case of mineral deficiency which would be remedied with yeast nutrient and water adjustment.

 

[grathan]

Oxygen is important. All-grain or extract doesn't really matter.


Which temperature controller do you have? I have an analog Johnson that swings like 8 degrees which sometimes puts the yeast to sleep.

 

[sgraham602]

As for water. Right now I build off of distilled.


My temp controller is the digital Johnson 2stage, don't use the heating side. Normally pitch in the mid 70s

 

[kh54s10]

As for water. Right now I build off of distilled.


My temp controller is the digital Johnson 2stage, don't use the heating side. Normally pitch in the mid 70s

Are you keeping the wort in the mid 70's? If so that is pretty warm and should actually give you BETTER attenuation. I do most of my ales in the low to mid sixties. I usually get very close to the predicted FG.

Are you making any mineral additions to your distilled water. That might be the source or your problem. I don't think distilled water has the right balance without additions.

 

[chickypad]

Have you checked the calibration on your mash thermometer, could it be you're mashing too high? 156 is toward the higher end anyway.

 

[sgraham602]

Mid 70s is what I pitch at. Ferm temps are held at 67. My thermometer for my mash is a thermopen, which is spot on.

My water starts as distilled and I build it up to the desired minerals per style.

 

[uatuba]

Actually, all-grain vs. extract does matter. If he is mashing too high, then he will get deceptive hydrometer readings (meaning lots of unfermentable sugars even though his OG may be on target or even slightly higher). Check your thermometer...

 

[grathan]

Some yeast strains are just lazy.

 

[twallin]

Sounds like all you can do is a change a few things to start eliminating problems. A calibration or you thermometer you use for mashing temps might be in order. Oxygenated wort and maybe add a yeast nutrient.

 

[grathan]

There was a thread here yesterday on calibrating the ThermaPen. There are 2 calibration dials behind the sticker on the back that I didn't even know about.

 

[AT-JeffT]

What yeast strain(s)? Was this not already asked?

 

[bigbeergeek]

All gravity readings are correct? Hydrometer or refrac?

 

[ArcaneXor]

Oxygenate, add nutrient, mash lower, calibrate your equipment, and pitch the yeast in the the low to mid-60s and start raising the fermentation temperature by 2 degrees per day after 4 days or so.

 

[LKABrewer]

Look into doing a forced ferment test. This will determine whether it is a hot side issue or a cold side issue.

 

[tagz]

I had three batches over-attenuate (90%)... Turned out my thermometer was reading +6* F. Thermopen should be pretty reliable, but you might want to check it anyway. Try boiling water and cup of crushed ice with water. At least you can eliminate that as a variable.

 

[sgraham602]

to answer some of the questions. All batches have been 001 or 007. I use refract prior to ferm and refract with calculation after ferm (used hydrometer a few times to confirm I had it right).

I am going to check my Therm and possibly do a forced fermentation test.

 

[bja]

It's all grain. Typically mashing between 152-156.

I had this problem for awhile. I started mashing at 148 and now all is well.

 

[Hopper5000]

I noticed you said your starters are from 1037 to 1066 OG. You don't really want to go over 1040 with starters as that can stress the yeast out and make them not ferment effectively. Are you using a stur plate?

 

[sgraham602]

1.037-1.066 is the OG of my wort. My starters are in the 1.035 range on a stir plate

 

[Hopper5000]

oh ok my mistake. i am assuming that you are getting vials that are fairly viable from a lhbs?

Are you reusing your yeast or are you buying new yeast everytime?

Are you unhappy with how the beer is turning out taste wise or are you just getting irritated at the numbers?

 

[sgraham602]

oh ok my mistake. i am assuming that you are getting vials that are fairly viable from a lhbs?

Are you reusing your yeast or are you buying new yeast everytime?

Are you unhappy with how the beer is turning out taste wise or are you just getting irritated at the numbers?

a little of both! I've been unhappy with a noticeable sweetness. Also had been plagued with a slickness, which I associated with diacetyl. But i believe that was because of my chest freezer placement, which caused a heating element to turn on. I think the heating element was so close to the fermentor that it was heating up some of the yeast way too much.

At any rate. I buy vials from my LHBS and they are always well within date.

 

[Yooper]

a little of both! I've been unhappy with a noticeable sweetness. Also had been plagued with a slickness, which I associated with diacetyl. But i believe that was because of my chest freezer placement, which caused a heating element to turn on. I think the heating element was so close to the fermentor that it was heating up some of the yeast way too much.

At any rate. I buy vials from my LHBS and they are always well within date.

One thing I was just reading about was the impact mash pH has on the fermentability of wort. It's not the whole cause, of course, because temperature and time also play a huge part, but a too-high mash pH can cause a less-fermentable wort. That made me think of this thread.

Have you checked mash pH at all during any of these brews?

 

[malaeum]

Deleted

 

[grathan]

@malaeum be sure to check the dates on your yeast packages. Also some recipes have a lot of unfermentable sugars. For example dark malts used in porters, or even crystal malt, and especially lactose.

 

[grathan]

@sgraham602 I have also noticed a slickness in my beers this year. It seems to go away with time though. 1.5 months (mostly in the keg) seems to be the sweet spot.

 

[sgraham602]

One thing I was just reading about was the impact mash pH has on the fermentability of wort. It's not the whole cause, of course, because temperature and time also play a huge part, but a too-high mash pH can cause a less-fermentable wort. That made me think of this thread.

Have you checked mash pH at all during any of these brews?

i have used some ph strips...but have not taken the time to really pay attention to the PH

 

[Yooper]

i have used some ph strips...but have not taken the time to really pay attention to the PH

Maybe consider using some brewing spreadsheets (if you know your water chemistry) to guestimate the probable mash pH. I'd shoot for 5.3-5.4 at room temperature, and that should enhance fermentability.

If you're not using any acid to lower your pH, and you're not using RO or distilled water, it's likely that the mash pH is higher than that, and possibly much higher.

 

[sgraham602]

I've been using the EZ Water spreadsheet and building up from RO. Looking at my last few batches, the room temp PH was 5.6

 

[Yooper]

I've been using the EZ Water spreadsheet and building up from RO. Looking at my last few batches, the room temp PH was 5.6

I'd try Bru'nwater (EZ is always reading low for me), as it's been really accurate for me (as tested with a pH meter). It is has a bit of a learning curve, but it's worth it!

I would try adding some phosphoric acid (or lactic acid if it's not much) to the mash to target 5.3-5.4 and see if that makes a difference. I think it will. If your mash pH is over 5.6 in actuality, that would explain (at least partially) the lowered fermentability of the wort regardless of mash temperature.