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DeepSea 04-25-2010 12:06 PM

high final gravity
 
My last two batches have had high final gravity,1.020. They were both 1.070 OG. I brew 10 gallon batches, all grain. I am using 1056 yeast with a 1 gallon starter. I always use oxygen to aerate. I use a single infusion mash ( batch sparge) at 155F with a mashout at 170F. Ferment temp has been a consistent 65F . 1056 yeast calls for attenuation of 73-77 percent. This should put me at 1.018 at 73% attenuation. Any idea what is causing this? Possible remedies?


DeepSea

Netflyer 04-25-2010 12:30 PM

A couple of possible ideas... W/out knowing the grist in the recipe I can't say if a component in that might be helping keep that high but what about mashing at a lower temperature? How long are you in the primary for? I use 1056 and have finished up in 1.012 range for OG's at around 1.072-1.075 and I checked and I was mashing at 152 for 90 min on that one. (IPA). Another amber ale recipe I make and use 1056 get's even lower FG's but it starts much lower too at 1.042. You could try raising your temp towards the final 1/3 of fermentation from 65 up to 68-70, might help too. 1.020 isn't that bad either :)

Yooper 04-25-2010 12:36 PM

I think it's the high mash temperature, without knowing more about your ingredients.

Is you thermometer accurate? If you're even 3 degrees off, you could be mashing at 158 or so, which would really give you a ton of unfermentables.

You could try mashing your next beer at 152 or so, especially if it's a pale ale or another beer that you'd really like to have finish at 1.012-1.014.

DeepSea 04-25-2010 01:16 PM

1.020 is not terrible but I was hoping for a lower final. Recipe called for a final of 1.015. It is a green flash west coast IPA.

Here is the grain bill.
84.2 14.00 lbs. Pale Malt(2-row) America 1.036 2
7.9 1.31 lbs. Crystal 40L America 1.034 40
7.9 1.31 lbs. Cara-Pils Dextrine Malt 1.033 2

I verified the thermos and they are accurate. I think I will mash at a lower temp. I currently strike at 170 and it settles at 155. I am mashing in a keg. What do you folks use for strike temp? Are you mashing in kegs?

Thanks for the input.

DeepSea

WenValley 04-25-2010 01:42 PM

+1 on the mash temperature being on the high side. I mash in a 40 quart Igloo cooler.

Beersmith brewing software takes a lot of the the guess work out of the "Strike Temperature" question. You can make adjustments for all of the mash factors such as starting grain temperature, grist to water ratio, etc. The software calculates the temperature of the strike water. I've found it to be very accurate.

Yooper 04-25-2010 01:45 PM

Quote:

Originally Posted by DeepSea (Post 2025539)
1.020 is not terrible but I was hoping for a lower final. Recipe called for a final of 1.015. It is a green flash west coast IPA.

Here is the grain bill.
84.2 14.00 lbs. Pale Malt(2-row) America 1.036 2
7.9 1.31 lbs. Crystal 40L America 1.034 40
7.9 1.31 lbs. Cara-Pils Dextrine Malt 1.033 2

I verified the thermos and they are accurate. I think I will mash at a lower temp. I currently strike at 170 and it settles at 155. I am mashing in a keg. What do you folks use for strike temp? Are you mashing in kegs?

Thanks for the input.

DeepSea

For an IPA, 1.020 is pretty darn high. You've got a lot of crystal, that's part of it. 2.6 pounds of crystal sure seems like a lot- about 16%, if my quick figuring is right. A high mash temperature, combined with that much crystal would definitely keep the FG high.

In my opinion, an IPA should be mashed at 150-152 so it'll finish lower. I like my IPAs to finish in the 1.010-1.012 range, depending on the OG and grainbill.

I only mash "thick" beers or heavy beers at 155 or over. My ambers are usually mashed at 153-154. Cream ales are mashed at 150 or so. Mash temperature plays a huge part in attenuation, as does the recipe of course.

ajf 04-25-2010 02:32 PM

Another vote for mashing at 150 - 152. I'd also reduce the crystal down to less than 10%. Both of those suggestions would help lower the FG.
One other possibility is the mash thickness. If you mash thick (about 1 qt / lb), then the FG will increase. If you use 1.25 qt / lb (or thinner), then the wort will be more fermentable.

-a.

kanzimonson 04-25-2010 08:55 PM

DeepSea, I love this recipe and brewed it up recently as well. I mashed at 154, and pitched with 1272 and my FG was 1.015. I agree with others that the first thing to attempt would be a lower mash temp.

I say to hell with people who tell you to reduce crystal malt. People say this all the freakin time on these forum, but I love crystal malt for every reason. I think there's an unfounded fear of overly sweet beers due to crystal. Sure, it definitely will increase sweetness but in an IPA as bitter as Green Flash's, it's exactly the balance you're looking for.

Clearly you've got a good recipe on hand (I see it's exactly the BN's recipe), and like Jamil says frequently (paraphrased), "The brewers aren't lying to you when they give you the recipe - you'll have to adapt it to your own system." For whatever reason, your system might require you to mash slightly lower than other people's systems to achieve the same results.

DeepSea 04-25-2010 09:12 PM

Quote:

Originally Posted by kanzimonson (Post 2025994)
DeepSea, I love this recipe and brewed it up recently as well. I mashed at 154, and pitched with 1272 and my FG was 1.015. I agree with others that the first thing to attempt would be a lower mash temp.

I say to hell with people who tell you to reduce crystal malt. People say this all the freakin time on these forum, but I love crystal malt for every reason. I think there's an unfounded fear of overly sweet beers due to crystal. Sure, it definitely will increase sweetness but in an IPA as bitter as Green Flash's, it's exactly the balance you're looking for.

Clearly you've got a good recipe on hand (I see it's exactly the BN's recipe), and like Jamil says frequently (paraphrased), "The brewers aren't lying to you when they give you the recipe - you'll have to adapt it to your own system." For whatever reason, your system might require you to mash slightly lower than other people's systems to achieve the same results.

This is the recipe from BN. I will mash at a lower temp next time. I made some mods to my system and am still working the kinks out. I have a pump so I may strike at 165 and if I have to add heat with recirc. I can do that. I just recently had green flash for the first time and love it.

Thanks,

DeepSea


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