What am i doing wrong?

Brewing processes and methods. How to brew using extract, partial or all-grain. Tips and tricks.

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What am i doing wrong?

Postby billd220 » Fri Jul 13, 2007 5:59 pm

This is probably a hard question to answer but:

What am I doing Wrong?

I switched to partial mash brewing from extract brewing and now I can't seem to get my F.G. low enough. I brewed an oatmeal stout and it stopped fermenting at 1.026. Then i brewed an amber ale and it stopped fermenting at 1.020

My O.G.'s seem to be fine but it seems like it wont finish. Is it because Im not getting full starch conversion on my mash? Maybe, i'm only really fermenting my DME. Wouldnt my O.G. be affected if i didnt get the full starch conversion.
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Postby brewer13210 » Sat Jul 14, 2007 6:10 am

Are you doing an iodine test at the end of your mash? That will tell you if there are unconverted starches at the end of the mash. What temperature are you mashing at?

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Postby billd220 » Sat Jul 14, 2007 8:33 pm

No i didn't do an iodine test so it is quite possible I didn't have full conversion. I mash at 158 but i struggle to keep the temp constant.
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Postby brewer13210 » Sat Jul 14, 2007 8:42 pm

158 is a bit high, you might want to shoot for the 152-154 range. I'd also do an iodine test the next time you brew.

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Postby mrocco » Sun Jul 15, 2007 1:29 pm

The higher the mash temp the less fermentable the wort. At 158, you're mashing at the higher end of the scale which I believe is going to lead to a higher FG, and and a sweeter beer. Even so, 1.020 ro 1.026 seems a little high, even at the high mash temp. I'm sure someone will correct me if I'm wrong.
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Postby billd220 » Sun Jul 15, 2007 2:48 pm

thanks Brewer and Mrocco. I appreciate the input. The truth is I may have been shooting for 158, but i think i'm all over the place. Sometimes the temp dropped and i had to heat it up again. Then it got too hot and i had to cool it down.

I read that typically yeast will ferment about 65% of the sugars so your FG will be somewhere about 35% of your OG. While Im getting my OG o.k., myFG is not getting where it should be.

Thanks for the suggestions though.
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Postby brewer13210 » Mon Jul 16, 2007 7:53 am

Another thing to keep in mind is that the enzymes are denaturing during the conversion, and denature faster at higher temps. So, depending on how hot the mash got, you could have destroyed the bulk of the enzymes before the conversion was complete.

When you're starting the mash, make sure you have a big spoon or other stirring implement, and keep stirring the mash until you have even temps throughout. That will help prevent hot and cold spots.

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mash temp

Postby slothrob » Mon Jul 16, 2007 8:39 am

1.026 is pretty high, even at 158
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Thanks

Postby billd220 » Wed Jul 18, 2007 10:54 pm

Thanks everyone....I appreciate the help.

I think part of my problem is that i mashed in a grain bag so that i could easily remove it from the pot. Its not real easy to stir when the grain is in the bag. I have a cooler i could use, but i worry that if the temp gets too low, i cant heat it back up and i'll end up having to add water.

Brewing is like golf. You watch someone who knows what they're doing and it looks easy. When you try to do it yourself...you find its not really easy at all. But its still a lot of fun.
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Stirring

Postby slothrob » Thu Jul 19, 2007 8:02 am

Stirring is very important.

Without a good mix at the beginning, your temperatures will vary within the mash, making your results unpredictable, and you may have "dough balls", or areas that never mix thoroughly with the water and don't mash well.

Without a good mix prior to runoffs, your sugars may be poorly dissolved or poorly extracted from the grain.

I use a cooler and, except for the first couple batches where I missed my mash temp by about 5
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