Under-attenuating.....looking for input/ideas

[Kealia]

The title says it all, I seem to have a track record of my beers under-attenuating and I'd like to get to the bottom of it.

I'll try to provide as much information as I can here and I'll answer questions/ideas as they come up.
I know it's hard to diagnose from afar and in written form but let's see if the collective brainpower here can help.

For the record, when I say it's not attenuating fully, this is across a variety of recipes, yeasts, styles, etc. For example, my IPL was OG = 1.060 and FG = 1.020 using 2 packs of WLP800 on a starter (required yeast count calculated by Mr. Malty). That's 66% attenuation on a strain that should get me 72% - 77%.

So, here we go:
- I'm using 99% all grain but do occasionally use extract
- Yeast varies from dry to liquid, sometimes I use a starter and sometimes I use extra packs (depending on timing/planning)
- I use EZ Water to calculate the ph of my mash but do not use a ph meter
- I typically mash at 153 for 60 minutes
- I've had no issues hitting my target OG and volume
- I temp control with an STC-1000 and typically start at the yeast's mid-range and ramp up after 5 days by a few degrees
- My water is basically a blank slate and I build it up using gypsum, salts, etc.
- I typically use yeast nutrient in the last 5 minutes of the boil
- I've checked my thermometer to verify it's reading 212 at boiling

My first thoughts were a faulty thermometer but I've checked it numerous times and this 'problem' goes back to my first days of brewing. I've rarely had a beer attenuate to it's full (yeast's) potential.

I'm making good beers, but I feel like I'm missing out on the ability to make a drier beer for my IPAs, etc. I've tried mashing lower in the past so maybe that is the answer and it's staring me in the face.....I could target 149 as my mash temps but help me out here - am I missing something obvious?
All questions/input appreciated.

[BlackDuck]

Do you rack into a secondary after the primary is finished?

[Beer-lord]

What about good aeration? Remember more than a year ago I mentioned a similar problem. I got a aeration kit and since then, it's only happened once it twice.
Lagers can be tricky but ales should be close to stated attenuation.



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[Inkleg]

For dryer IPAs, mash at 148 and sub a pound of grain for sugar. Water boils at different temperatures, check your thermometer using a Ice Bath.

[Dawg LB Steve]

My two cents. Aerate with Oxygen. I use the bernzomatic type cylinders of oxygen that can be purchased at the big chain hdwr stores, picked up the aeration setup from AIH has hose and diffusion stone. Mash Ph still could be part of the problem even though adjusting your water, mash Ph may still be a bit higher than optimal, should pick up a Ph meter. Once I started adjusting my mash Ph to stay in the 5.2 (lighter)-5.6 (darker) range and started using O2 it almost seems I have gotten a slight over attentuation by a couple points from projected FG.

[MadBrewer]

What is your mash thickness? It may not be a big factor but IME a thinner mash does help to make a more fermentable beer. I use the opposite, when brewing Stouts and Porters, I mash thick for better mouthfeel and less fermentable wort. Its subtle and may not be a big factor for some but I feel like I can tell a difference.

153* is pretty middle of the road for most beers, but I have heard it a time or two that one brewers 153* for example is anothers 155*. Again, small factors but they can all add up. What about raising the fermentation temps a couple degrees after day 4 or 5? Say if you pitched and fermented at 66* for an ale, do you let it rise to 68-70* after day 4 or 5 of fermentation or do you keep it set the whole fermentation? Raising the temps can help push them yeast along till the end.

[ScrewyBrewer]

Oxygenating your wort will definitely help with attenuation, as will a healthy pitch rate and the freshness of the yeast. With that said mash temperature influences the enzymes that convert starches into sugars that yeast will convert to alcohol, which is why we all love beer.

The alpha amylase enzyme breaks down starches into glucose (dextrins), producing non-fermentable sugars that add fullness and body to beer. The optimal temperature range is between 145-158F and the optimal pH range is between 5.3-5.8.

The beta amylase enzyme breaks down starches and sugars into maltose, producing thinner more highly fermentable sugars that are most preferred by yeast. The optimal temperature range is between 131-149F and the optimal pH range is between 5.0-5.6.

nonameIPA-3a-sml.jpg (27.53 KiB) Viewed 621 times

As you can see there is a 'balancing act' that takes place in the mash, higher temperature combined with higher pH may be something to look into possibly. The IPA that I kegged last night had an OG =1.057 and an FG=1.009, or 80% apparent attenuation, using wlp-001 pure pitch packets. It was fermented at 65F which is 3F lower than wlp-001 optimal temperature, but the results produced a well attenuated 6.3% IPA. The 65F temperature was held for 7 days, after which it was bumped up .5F daily until the beer was packaged.

[Kealia]

Answering the questions asked here:
- No secondary
- Aeration? Yes. I use pure oxygen in the red tanks with a stone. I run for 90 seconds at a rate that just has bubbles breaking the surface, no higher
- Mash thickness I use is 1.5q/lb
- I've been having these "issues" since I was doing BIAB and now am doing a 'traditional' mash and sparge

I'm thinking that maybe it is my temp. I need to either mash lower (target 149/150) or get a new/second thermometer and use/check that one.
Everything else seems to be inline.

Apprecaite the thoughts...keep 'em coming. And if anybody is looking for a Christmas gift idea...maybe a new thermometer

[ScrewyBrewer]

Apprecaite the thoughts...keep 'em coming. And if anybody is looking for a Christmas gift idea...maybe a new thermometer

Sure thing, I can always use another thermometer

[Inkleg]

Asheville...........>Inkleg drops mic<

[BlackDuck]

Ron...reason I was asking about the secondary was to see if possibly you were racking to the secondary too early, thus reducing the exposure to the bulk of the yeast. But, since you don't secondary, I'm no help here. Carry On!!!

[mashani]

I can't think of anything folks haven't already said. I tend to over attenuate a bit but I am pitching a lot of yeast (Pro Brewer 0.75 to 1.25 on this calculator depending on my OG - http://www.brewersfriend.com/yeast-pitc ... alculator/) and also have that random brett thing which adds to it. Even in my extract beers I get good attenuation, but that's because I use fresh stuff and I will also use a bit of sugar in things without any second thoughts, I tend to apply "British and Belgian tricks" to pretty much anything that I don't want to turn out chewy. When I do cold water top ups, I will actually oxygenate the cold water before I top up, I'm sure that helps too (near ice cold water can hold more oxygen in solution then 60-70 degree water). I also tend to mash 152 or < for most beers (some beers I mash at 147-149).

[Kealia]

Cool, I'll go with a lower mash this next time around and see what happens. I've always treated my yeast right (using fresh yeast, correct amounts via Mr Malty) and giving it oxygen.

If the lower mash doesn't work, I'll look into a good thermometer next to see if I'm mashing higher than intended. Fortunately, I haven't ended up with a sweet beer yet - just wondering if they could be even better by getting the dman yeast to do their job completely!

[John Sand]

Check your hydrometer?

[MadBrewer]

What is your usual fermentation routine? Do you raise temps after 4-5 days of fermentation or just let it ride the whole time at your determined fermentation temp?