Apparant Attenuation & Fermentation Issue

What went wrong? Was this supposed to happen? Should I throw it out? What do I do now?

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Apparant Attenuation & Fermentation Issue

Postby ripsnub » Thu Feb 16, 2006 1:53 pm

This is a first for me. Put together a modified blond ale recipe with 6-row, 20L, 40L, wheat, and flakes oats adjunct. Total grain weight was just at 10 lbs. Maintain Mash temp between 152 - 160. A couple times the temp rose up to about 170-175 as I was using a new propane cooking system and was on the learning curve keeping the temp constant. After 60 min failed iodine test for starch conversion, ran another 30 mins, again failed, after another 30 minutes again the dark purple interface. So moved onto sparge, boil, primary. OG was a bit lower at 1.041 but batch size ended up at 5.5 gal. Fermentation noticed in air lock after about 12 hours, but was slow and steady at 10 - 20 vents per minute at peak. All my previous batches have had a real vigorous fermation cycle for at least 8 hours with 40-50/min but not this time, then slowed to 1/min at day 3. Opened up last night day 4 and moved to secondary with gravity reading at only 1.020. Without the proof of complete starch conversion and the atypical hydrometer readings I am looking for some thoughts. Wondering if the couple high temp spikes during mash caused problems or if the flakes oats (pre gelentaized) was an issue. Thanks for any ideas... SW - Gresham OR.
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Postby BillyBock » Fri Feb 17, 2006 5:07 am

Here's some things I thought of:

Is the room cooler than usual which would cause slower activity?

Is your fermenter a bucket? Maybe the lid's not on tight and CO2 is escaping through there?

Maybe average mash temp was too high causing you to have too many dextrins which are harder for the yeast to eat?
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Postby ripsnub » Fri Feb 17, 2006 2:45 pm

I am thinking the last comment is probably the one as it is clear that there still was starch left in the mash and the temperature was higher than needed on several occasions, I am just not sure exactly what affect that has on the conversion process. The location of the fermenter is that same place in the house and is maintained around 66 - 70 degs. The lid may be an issue with the visual CO2 production in the vent but that does not explain the low F.G of 1.020. Another thought was that the real aggressive yeast fell out in the trub and was unable to work on the remaining sugars, so maybe I should of tried to resuspend before I racked to secondary. There was a pretty good amount of frogsh-t in the bottom of the bucket - at least more than I am used to seeing. So maybe I have a weak, starchy golden ale to choke down in a couple weeks, it smelled fine, I just hate when a batch doesnt go the way it is supposed to go !! :cry:
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Postby ripsnub » Tue Feb 21, 2006 2:58 pm

Also wondering if the 6-row versu the 2-row might of caused a lower yield?
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