Homebrewers Association | AHA Forum

General Category => Yeast and Fermentation => Topic started by: bendbrew on November 15, 2009, 09:03:09 AM

Title: Fermentation and High OG
Post by: bendbrew on November 15, 2009, 09:03:09 AM
First off thanks to everyone who responded to my posts/questions regarding foam stoppers and OG of a starter.  Yesterday, I brewed a "Double IPA"-Extract/Specialty grain recipe.  I miscalculated water additions and ended up with 5.5 to 6 gallons of wort-OG was 1.074.  I racked into the fermentation bucket allowing quite a bit of splashing (racked at 65 degrees).  I then used an O2 canister and stone-three times for about 10 to 15 seconds each-swirling the stone around the bottom via the stainless steel tube.  I then pitched my 1500ml of starter and another fully puffed out pack of Wyeast 1056.  FYI-the starter was created the day prior using a way too high OG starter of 1.065 and a stir plate.  It is now the 16 hours later-early I know but no activity in the Airlock.  The lid is sealed tight, the inside part of the airlock is pushed up.  Should I have any concerns? Thanks-
Title: Re: Fermentation and High OG
Post by: bonjour on November 15, 2009, 09:37:37 AM
In a word, No.

patience is all that is needed.  If you have nothing after day 3, then let us know, but check your gravity first.
Title: Re: Fermentation and High OG
Post by: tom on November 15, 2009, 09:50:54 AM
Sounds fine. What temperature is it at? Get a blow-off tube ready!
Title: Re: Fermentation and High OG
Post by: bendbrew on November 15, 2009, 09:59:10 AM
I am fermenting at 67 degrees
Title: Re: Fermentation and High OG
Post by: bonjour on November 15, 2009, 10:24:55 AM
I am fermenting at 67 degrees
That's a good fermenting wort temp. 

For those that are on the early part of the learning curve,
The yeast don't care what the room temp is, only what the wort temp is, with the difference being 5-10F.

Fred
Title: Re: Fermentation and High OG
Post by: bendbrew on November 15, 2009, 10:47:43 AM
Thank you Tom and Fred-

There is much to learn in this hobby-can be frustrating for the newbie but it is also fascinating.  Shortly after my temperature post, the airlock began to show rapid activity!

Bill
Title: Re: Fermentation and High OG
Post by: bendbrew on November 16, 2009, 07:22:44 AM
Fermentation was extremely vigorous from 9am yesterday till when I got up this morning at 6.  Last night I had to rotate out sanitized airlocks because they were getting clogged.  This morning-airlock clear and not even a bubble out of it.  Lid is tight as is airlock.  Could primary fermentation be that quick?  Yeast is still almost reaching the top of the bucket.
Title: Re: Fermentation and High OG
Post by: bonjour on November 16, 2009, 08:04:16 AM
It could be Bill,
Grab a gravity reading for reference and check it again in a couple of days.

Fred
Title: Re: Fermentation and High OG
Post by: bendbrew on November 17, 2009, 05:53:09 PM
I neglected to take a reading after the one day of vigorous fermentation but here is the latest:  OG on Saturday was 1.073, today, Tuesday with no obvious signs out of the airlock the gravity is 1.035 via the refractometer but 1.023 via the hydrometer (corrected for temp).  I will recheck over the weekend.  I wonder if the higher refractometer reading may be due the yeast in the mix-I let the sample settle before the hydrometer reading).  Thanks for the continued support and advice.
Title: Re: Fermentation and High OG
Post by: a10t2 on November 17, 2009, 07:17:19 PM
Are you using a refractometer FG correlation to correct the reading? It can't be converted directly to SG once there's alcohol in solution. (And actually, in my experience, the correlations aren't too good either.)

http://onebeer.net/refractometer.shtml (http://onebeer.net/refractometer.shtml)
Title: Re: Fermentation and High OG
Post by: bendbrew on November 20, 2009, 05:09:54 PM
It was a corrected reading.  I will draw another sample for a reading this weekend.
Title: Re: Fermentation and High OG
Post by: bonjour on November 20, 2009, 09:49:14 PM
If you provide your uncorrected readings we can check that you are correcting correctly. 

Fred
Title: Re: Fermentation and High OG
Post by: bendbrew on November 21, 2009, 09:15:58 AM
Uncorrected:  Brix-9  and SG at 68 was 1.022 
Title: Re: Fermentation and High OG
Post by: a10t2 on November 21, 2009, 09:29:59 AM
Assuming an initial reading of 17.5 (to give your 1.073 OG) a final reading of 9 Brix correlates to 1.013. That's using the calculator I linked to earlier, which is the same one built into ProMash (and probably any other brewing software).
Title: Re: Fermentation and High OG
Post by: bendbrew on November 21, 2009, 09:59:34 AM
I got my reading from Beer Alchemy-I am on a Mac.  My original Brix was 18.2 and 9 at my last reading.  For the post initial fermentation, where I got the brix of 9, I took a hydrometer reading as well.  That read as 1.022 at 68 degrees
Title: Re: Fermentation and High OG
Post by: a10t2 on November 21, 2009, 10:31:20 AM
That still works out to an FG of 1.011. I downloaded BeerAlchemy and plugged those numbers in, and it gave me 1.012. Are you sure you're entering the right inputs (current Brix reading, and OG in SG)?
Title: Re: Fermentation and High OG
Post by: bendbrew on November 21, 2009, 11:09:33 AM
You're right-I entered it wrong.  Thanks for the correction.  What I don't understand is when I tested it with they hydrometer at the same time it read 1.022 at 68%.  That is a large discrepancy.  I will retest either today or tomorrow
Title: Re: Fermentation and High OG
Post by: a10t2 on November 21, 2009, 01:23:22 PM
I've never seen a discrepancy that large, but in my experience the refractometer correlation rarely agrees with a hydrometer reading.
Title: Re: Fermentation and High OG
Post by: wilypig on November 23, 2009, 07:58:48 AM
One thing to remember about yeast and O2 is that in the presence of O2 yeast will want to reproduce and will not start any noticeable fermentation until the Lag phase (all O2 used up) is done. The more O2 you use the longer the lag time but the shorter the actual fermentation due to overall cell count. 
Title: Re: Fermentation and High OG
Post by: denny on November 23, 2009, 09:59:23 AM
I thought that the Crabtree Effect said that in the presence of a >.5 % glucose solution that fermentation starts immediately.  Incorrect?  Or is that what you were referring to by "noticeable fermentation"?

One thing to remember about yeast and O2 is that in the presence of O2 yeast will want to reproduce and will not start any noticeable fermentation until the Lag phase (all O2 used up) is done. The more O2 you use the longer the lag time but the shorter the actual fermentation due to overall cell count. 
Title: Re: Fermentation and High OG
Post by: a10t2 on November 23, 2009, 11:25:22 AM
That's my understanding of the Crabtree Effect as well, although the yeast will still respire aerobically until all the O2 is consumed. Otherwise there would be no reproduction in wort at all.