Homebrewers Association | AHA Forum

General Category => Yeast and Fermentation => Topic started by: tesla_hv on November 10, 2009, 01:21:08 PM

Title: Delay in fermentation
Post by: tesla_hv on November 10, 2009, 01:21:08 PM
I pitched the yeast into my last batch about 40 hours ago and there is still almost no kreusen on top and no airlock activity.  I'm not really worried about it just puzzled as to why a delay in this batch.  I did things pretty much the same as my past ten or so batches.  Maybe a bit lower pitching temperature but that's it.  Usually I get a very active fermentation in eight hours or so.  Any thoughts?
Title: Re: Delay in fermentation
Post by: bonjour on November 10, 2009, 01:32:22 PM
I'd give it until tomorrow and then, if nothing is happening, post in detail what you did.

A few thoughts (bucket) lid is not sealed, airlock is empty, air lock not sealed, yeast is just taking it's time, this is a bigger beer with the same amount of yeast. 
How much is a "bit" lower on pitching?  What yeast strain? Beer OG?  How much yeast was pitched?  from where (yeast cake, starter, etc.), (dry yeast) how many packets/grams?  what was your rehydration procedure?  etc.

Fred
Title: Re: Delay in fermentation
Post by: tesla_hv on November 10, 2009, 01:49:30 PM
OG = 1.09.  The yeast is WLP-001 California Ale.  I did a two-part yeast starter (0.7L/0.7L).  No airlock yet, a blowoff tube instead.  I usually pitch about 66-68F.  This time was closer to 62-64F.  Also, I use a turkey basting tin for my swamp cooler.  I usually add tap water and rotate out ice packs.  This time I used ice water up to about 4" in depth.
Title: Re: Delay in fermentation
Post by: jackfromjax on November 10, 2009, 01:59:40 PM
Was there a larger than 5 degree temperature differential between the starter and wort?  If so, the yeast could be in shock.  The lower pitch temp could have also extended the lag phase.
Title: Re: Delay in fermentation
Post by: majorvices on November 10, 2009, 02:14:01 PM
Was the starter on a stir plate? .7 L is on the hair edge of being too small unless you are using a stir plate. I would have used at much larger starter either way.

62-64 degree pitching temp is actually ideal for this strain but it depends if you pitche nough yeast or not. Regardless, I would give it another 24 hours before stressing too much.
Title: Re: Delay in fermentation
Post by: jds on November 10, 2009, 02:57:20 PM
When you say a 2-part starter, do you mean two separate 700ml starters, or one 700 ml starter decanted and charged with another 700 ml of wort?

My sources (a brewer I trust pretty well) tell me that for starters under optimum conditions, the yeast cell volume will be in the neighborhood of 10-15MM cells per (ml *P) of 1.040 wort, which is 100 to 150 X 10^6 cells per ml of starter, regardless of original cell concentration.

Other sources (Jamil Z's website, and Palmer) state the optimum pitch rate for an ale to be around 1MM cells / (ml *P)

Assuming you have 5 gal (19000 ml) of wort at 22 *P, you need:

19000 ml * 1MM * 22*P = about 4.2 X 10^11 cells.

for optimum 1.040 starter, you'd need 4.2 X 10^11 / 150 X 10^6 ml of starter volume, which is 2800 ml of starter, or 2.8l.

Since you made 1.4l of starter, you're underpitching by about 50% (assuming two separate 700ml starters). If you decanted a 700 ml starter and added another 700ml of wort, you probably didn't increase the cell count much, and therefore only pitched about 25% of the optimum cell count. While not awfully low, either condition is low enough to expect more lag than normal.  You'll probably be fine once things take off. I wouldn't even start worrying until 72 hours after pitching.
Title: Re: Delay in fermentation
Post by: smurfe on November 10, 2009, 03:05:44 PM
My guess would be a combo of lower temps for fermentation and a small yeast count for a 1.090 beer. I probably would of had a minimum of a gallon starter for that one.
Title: Re: Delay in fermentation
Post by: tesla_hv on November 10, 2009, 03:22:04 PM
One 0.7L, decant, than another 0.7L.  I can't find the link to a tech article outlining this technique.  Does anyone have this link?  It described the technique and also gave predicted yeast counts for various volume scenarios in both one-part and two-part starters.
Title: Re: Delay in fermentation
Post by: tesla_hv on November 10, 2009, 05:49:05 PM
Ok, I found the link.  First, according to Mr. Malty's pitching rate calculator, I would need 305 billion yeast cells for this batch.  According to the information provided in this link,

http://docs.northernbrewer.com/pitching_rate.html

a 0.5/0.75L starter would result in a yeast count of 318 billion cells.  If this information is true, I do not think that underpitched by much if at all.
Title: Re: Delay in fermentation
Post by: a10t2 on November 10, 2009, 06:14:17 PM
That NB document is incorrect. They started with the calculator on the WYeast site (http://www.wyeastlab.com/hb_pitchrate.cfm (http://www.wyeastlab.com/hb_pitchrate.cfm)), then converted from gallons to L for the single-stage starter figures, but forgot to convert for two-stage. I've emailed NB about it several times but never gotten a response.

Edit: Using the WYeast calculator directly, 700 mL -> 158 billion cells. (Their calculator assumes no growth if the second stage is the same size or smaller.)

FWIW, the NB priming sugar calculator is also incorrect in that it uses the same fermentability for cane sugar and corn sugar. I've been banging that drum to no avail as well.
Title: Re: Delay in fermentation
Post by: hopshead on November 10, 2009, 07:10:14 PM
A couple of questions.  When I first started making starters I did not make them correctly and found out my starters were way above 1.040 SG, thereby stressing the yeast and not growing them in ideal conditions.  How did you make your starter?

Second, is the fermenter still cooled to 62 degrees, if so, I might let it warm up a bit to mid to upper 60s until fermentation is evident. 

Also, was it apparent that your starter was good?  I.e. were the yeast alive and kicking off CO2?  If not the yeast pitch may have been bad. 

If I went over 48 hours with no sign of fermentation and I was using Wlp001 or wyeast 1056, I would pitch two or three packets of safale us-05 in a 1.090 gravity beer just to make sure I didn't loose that good wort.
Title: Re: Delay in fermentation
Post by: majorvices on November 10, 2009, 08:00:46 PM
If you are on a stir plate 700ml is alright. If not it is too small. Thats aid I use a stir plate and I never make a starter smaller than 1L.
Title: Re: Delay in fermentation
Post by: tesla_hv on November 10, 2009, 11:57:44 PM
Well the puzzlement here is that I did everything the same as before and now it is way past 48 hours and still no activity.  I lost patience and re-pitched a packet of hydrated US-05 and EC-1118.  It may be overkill but hey I'll raise my glass in celebration of this brew when it's done.  I hope that I have since leaned what I did wrong if anything.   It's all a learning process isn't it??
Title: Re: Delay in fermentation
Post by: jds on November 11, 2009, 09:13:56 AM
It's funny how thing happen that way, isn't it? Every now and then, something just goes 'round the bend, and there's no knowing why. 

I've been waking up some Pacman yeast for a brew since Sunday. I was starting to worry about it just a bit, then I came home from work yesterday to find a big raft of foamy yeast on top of the starter, even on the stirplate with foam control added.  I guess it's awake.
Title: Re: Delay in fermentation
Post by: bonjour on November 11, 2009, 09:17:44 AM
let us all know when it kicks into gear.

Fred
Title: Re: Delay in fermentation
Post by: tony on November 11, 2009, 11:45:17 AM
How well did you aerate and did you use pure O2 or other means if you in fact did aerate?

That's a hefty gravity for a yeast to swallow if you under pitched, unde raerated, or are starting
fermentation at a lower than optimum fermenting temperture.