mhellad

Recipes 

Okay, so before I go crazy...I need some help from you fine experts on this board. Hopefully I'm just overlooking something simple. Here is the problem: I'm on my sixth batch of AG that has only gotten down to a FG of 1.020. I've gone way too long now without a successful homebrew and I'm just left scratching my now hairless noggin since I've pulled the rest of it out in frustration. For a few years I did extract and partial mashes and never really ran into a problem with OGs or FGs but this is killing me. I'll start with listing the technique/equipment for the problematic batches I speak of that have stayed constant: I mash in a 10 gallon pot with a mash screen using 1.3 quarts of tap H20 per lb of grain. Mash starts out around 155-7 and ends around 150-153. I batch sparge until I have 6 gallons of runoff. Full boil for 60 minutes with Whirfloc at 15 min. Chilled and into the fermentation bucket within 30-60 minutes. OGs have all been in the 1.050-55 region. Fermention has been in a temp controlled fridge at 165-170 with the FG usually being checked after 14 to 21 days. Here are any differences that I can think of: Different recipes. Grains from different suppliers (therefore different crushers). The first batch was shaken and vigorously stirred prior to pitching yeast (never a problem with all the extract and partial mashes). All other batches used pure O2 through a stone. I've used White Labs, Wyeast, Nottingham, and Safale. I've re-warmed, I've re-stirred, and I've even re-pitched a couple of times. I spoke with WYEAST and they ran me through a forced fermentation test which I've done on the last few batches and did not change the result. Same result on EVERY batch- a FG of 1.020! My hydrometer reads correctly...my thermometer reads correctly...and my fridge temp reads correctly. I've had one AG come out with appropriate numbers when I first experimented with AG but that was doing two separate mashes because I only had one 5 gallon cooler...but go figure, it came out perfect and fermented fine. Is it my water?...it tastes great and never seemed to be a problem with extract and partial mashes. Can someone please advise on something that I'm overlooking or messing up?! I just find it very strange that every batch ends up at 1.020 and nothing else...what is it about this number and why does it taunt me!? Thanks for any help!

danielinva

Recipes 

The only thing that really strikes me as a potential cause is your mash temps. 155-157 will tend to produce very malty brews. Try knocking that down to around 152-153 initially and see where that gets you.

smizak

Recipes 

+1

You could let your mash go a little longer too.

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rod

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^^^^ what they said - too high a mash temp

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Ki-ri-n

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There's your problem

Sorry, I have nothing new to add.

mhellad

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I will try bringing the mash temp down a bit. Since it starts at 155ish and finishes around 150-152s then I figure it averages in the middle somewhere. Still too high? Also, someone mentioned to me today that perhaps my pH is too high. Never checked it but could this be an issue? Any hints for saving the two batches sitting in my fridge now? I was also told to maybe try a yeast nutrient/re activator to my stuck batches now and see what happens. Thanks again!

twoodward15

Recipes 

you should start around 152 at most for a general purpose beer and finish wherever it finishes. Don't start high expecting it to drop. The drop is ok. Start at 152 and tell us what happens. Also, if you're using a lot of carapils, try dropping that as well

Yooper

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What kind of mash tun do you use? I have a cooler, and I preheat it, and lose less than 1 degree in an hour. If you're losing that much temp, then you need to insulate your MLT or do something differently.

I doubt it is a pH issue- I mean, you're getting conversion. Make sure you calibrate your thermometer, too- if you're even a couple of degrees off, you could be mashing at 160!

"Around 157" isn't good enough, to be honest. I mash at precisely 153 for most of my American pale ales/IPAs. I don't even drop to 152 by the time the mash is over. For my Dead Guy clone, I mash that at 156 (it's a big, thick, malt bomb), and for some beers I mash as low as 150, depending on the style.

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pkeeler

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Hard to say more without knowing how much crystal malt you are using and what yeast strain. If you are using 20% crystal and mashing at 158, then you will get a lot of unfermentables. Even more so if you are using one of the less attenuating yeasts.

ajf

Recipes 

It could be the starting mash temperature. Alpha amylase (which is responsible for getting good attenuation) gets denatured pretty quickly at that sort of temperature.
It could be your water. If it is low in calcium, I have heard that alpha amylase does not perform very well.
It could be your mash thickness. Alpha amylase gets denatured more quickly in a thinner mash.
For the cases when you used liquid yeast, it could be that you didn't make a starter.
My guess is that it is a combination of these things.
I'd start by reducing your starting mash temperature. If you do this, you will need to insulate your pot, or maintain the temperature by adding infusions or direct heat. Insulation gives you the least chance of error, but is the most expensive.
If your water is low in calcium (like less than 50ppm), then that is easily treatable by adding some Calcium Chloride and/or Gypsum to make up the defficiency. You want between 50 and 150 ppm for brewing. If you have a municipal supplier, they should be able to give you the Calcium concentration. If you have well water, you can get an analysis for Ward Labs. You need test W6. Alternatively, you could make a brew using RO water (which is essentially devoid of all minerals) and adding brewing salts to adjust the Ca concentration. See http://www.ezwatercalculator.com/ for an excellent calculator that will give you the ppm values for all of the important ions, and see http://www.howtobrew.com/section3/chapter15-4.html for grams to teaspoon convertions.
I'd ignore the mash thickness factor. I mentioned it because a reputable source had said it was a factor, but you are not using a very thin mash, and I think that most members of this forum use a mash thickness similar to yours without any problems.
Making a yeast starter for liquid yeasts however is very important. On the few occasions that I didn't to this, I got lousy attenuation, and it took a long time to achieve the poor results.
I have relatively soft water with low levels of calcium, and I also use liquid yeast (usually WLP002) and make a starter.
I treat my water with CaCl2 and/or CaSO4 to make up the calcium deficit. I usually mash at 150F for 90 minutes in a cooler, and usually achieve much higher attenuation
figures than Wyeast or White Labs state in their descriptions.

-a.

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