Pages: 1
Unbelievable attenuation
Brewed a batch of low gravity Chinook Pale Ale on the 8th of March. Recipe below:
5 lb. Pale 2 row
2.5 lb. White Wheat
4 oz. Aromatic
4 oz. Crystal 60L
1 lb. Turbinado
.5 oz. Chinook (11.5%) @ 30
.5 oz. Chinook (11.5%) @ 20
.5 oz. Chinook (11.5%) @ 10
.5 oz. Chinook (11.5%) @ 5
Whirlfloc @ 10
Safale US-05 @ 78 F
Single Infusion @158 F for 60 mins.
Batch Sparge
OG: 1.044
1.012 - 1.014 is what I normally get for FG with this beer. I ended up at 1.002.
The only thing I did differently than normal is boil a pinch of Fermaid.K in the water I used to rehydrate the yeast.
I left almost all of the trub in the BK, as I normally do, so the wort was very clear after transfering to fermenter. An hour or so after pitching I noticed that there was a lot of coagulated matter in the fermenter which remained for a day and a half as active fermentation took place.
Fermentation appeared rather slow after a lag of about 5 hours and stopped on the second day. At this time the coagulated matter settled out and left the beer crystal clear.
I was afraid I had a stuck fermentation and left it sit until today whan I pulled a sample to see. Much to my surprize, it is at 1.002.
Could it be that the Fermaid-K made thismuch difference? I find it hard to believe, but I double checked my hydrometer in 60 F water and it is accurate.
Any comments?
Wow that's about 95% apparent attenuation. I've only reached close to that with a saison strain, 146F mash temp, and a pound of corn sugar.
Are you sure your thermometer is correct? I wouldn't expect a beer mashed at 158F to reach such a low FG even with a pound of turbinado sugar. When you checked your mash temp did you stir well and check it in a few spots?
I was amazed too! I stir very well and leave a floating thermometer in the mash and take a core reading just before running. All three of my thermometers match +/- 2 degrees.
I'm just wondering if the Feraid-K is really making a big difference. The coagulation and clarity during ferment was amazing too. Going to brew the same recipe tomorrow with cane sugar and Palisades instead of Turbinado and Chinook and try it again. Will post results.
Thanks for the reply,
Bob
Got to thinking, a couple of months ago I brewed a batch that I mashed at 48 degrees and got very low efficiency, about 48% if I remember right. That, and your comment about mash temp. got me thinking, so I tested my thermometers against an old mercury oral thermometer at 100 F. All three read high, with the floater I use in my mash being the worst at about 7 degrees.
That explains both the high attenuation of this batch and the low efficiency of the other one. Who'd a thunk it? Three thermometers all off in the same direction and within a couple of degrees.
BTW, The yeast in the batch in this post was S-04, not US-05. And I don't even drink on brew days anymore.
Anyway, thanks for kick starting my old brain.
Bob
I would suspect that you may have picked up a wild yeast or bacteria that chewed on some of the non fermentables, driving down your gravity. Its possible to get a bit of an infectiont that doesn't have any strong off flavors.
All things being equal, if your equipment was operating properly (thermometers etc etc) that is really the only thing that could drive your attenuation so much.
If you bottle this beer keep an eye on it and see if it keeps going.
brewchez wrote:
I would suspect that you may have picked up a wild yeast or bacteria that chewed on some of the non fermentables, driving down your gravity. Its possible to get a bit of an infectiont that doesn't have any strong off flavors.
Yeah I thought that too but didn't mention it because the OP was dated only 13 days after brew day. Do you think an infection could bring a gravity down so low in such a short time?
FPB-
Anything is possible. Its a tough topic to talk about sometimes, and I don't mean to call anyone out on sanitation.
However, it inevitably happens at least once to everyone, so its not something to be upset about.
But that might not be the thing reason. Its no possible to get that level of attenuation with brewing yeast alone like that. So either a calculation went wrong along the way, a volume estimation was off, an instrument reading was off. There's many things. If its not one of these operational things, then the only thing left in my view is something else chewing away on the non-fermentables.
It tasted awful good when I took a gravity reading, but time will tell. I'm pretty anal about sanitization, but chilling outside with a breeze blowing definately leaves the possibility of infection open.
BTW, I brewed with the same grain bill with different hops and cane sugar instead of turbinado Monday. Unlike the sluggish fermentation of the batch in question, this batch is fermenting violently and there was very little coagulated matter prior to the onset of fermentation. Hit the same mash temp within a degree and efficiency was identical. There was definately something wierd about the subject batch. I'm gonna be pissed if it turns out to be a great beer and I can't figure out what made it great 
I''ll keep you posted on the subject beer.
BBB wrote:
It tasted awful good when I took a gravity reading, but time will tell. .
When you say tasted good, I assume you mean no off flavors were detected. But how did it taste for dryness/sweetness? A 1.002 beer has no sweetness left in it at all. It should taste almost like a brut champagne. I have had some saisons in the mid single digits, and they are quite dry, and high carbonation makes them drinkable. Just as a beer that should finish at 1.014 tastes way overly sweet at 1.020, the same beer should taste remarkably dry 12 points lower.
You used some crystal malt, which holds some fermentables back, and even though your thermos were off, 158-7 degrees of variance, still is 151, which is a perfect mash temp for this. S-04 although being a quick starter and violent fermer, still is slightly less attenuable than us-05. The whitbread should leave some maltiness behind.
So if this beer tastes even mildly normal, then I would point my finger at the gravity reading itself. You said you double checked the hydrometer, but could there have possibly been a piece of break material or something that caused the glass to stick to the test tube holding it down?
Most important thing is it tastes good.
You now... the paper scale in the hydro could have moved too. If it was dropped or jarred.
Like thirsty said, the ingredients and temps you are using. Its just hard to imagine a 1.002 reading.
Its tough to get a 1.002 reading with any beer really.
Are you sure it wasn't 1.020?
I have never had an FG that low, so I did a double take. There is the possibility that something helped the hydrometer float, but I spun it a couple of times to be sure of a good reading.
As for the taste, I honestly can't remember anything but that it tasted decent for being flat and warm. i'll try to be more objective when I bottle next monday.
OK, All carbed up and ready to sample. MMMMMMMMMMMM! This brew turned out just fine. Corrected FG was 1.004. A little dry, but actually well balanced and absolutely no off flavors. Amazing considering that I put it on the yeast cake at 82+ degrees.
Bought a good digital thermometer and now I'm hitting OG within a point and atttenuation is in the expected range for my beers.
I thought I was going crazy after checking 3 thermometers against each other and finding them all within a couple of degrees and still having problems. Lesson learned: check thermometers in the temperature range they are used (mash temps.) in and not at 212F.
Thanks again for the replies.
Bob.
brewchez wrote:
You now... the paper scale in the hydro could have moved too. If it was dropped or jarred.
Like thirsty said, the ingredients and temps you are using. Its just hard to imagine a 1.002 reading.
Its tough to get a 1.002 reading with any beer really.
Are you sure it wasn't 1.020?
AHHH, BOTTLE BOMBS! LOL
DC
Pages: 1
Search Home Brewing Knowledge Base
Custom Search
|