Propagation

[bmantzey]

I've got a starter going right now with 2308 Munich Lager yeast in it. The starter is for a Celebrator Doppelbock clone. It's going nuts in my new 1-gallon glass jug and it's pretty fun to watch.

I was wondering how many yeast cells I'll end up with after letting it incubate for a couple days. I used the propagator packet, which starts at 25 billion cells in the packet. At the end of a ~48 hour period, how high will the yeast cell count be? I'm sure there's a way to calculate this based on gravity of the wort, current cell count, temperature, etc., but does anybody have any rough guesstimate as to what it may end up at?

Thanks.

 

[fixitoscar]

mrmalty.com will calculate that for ya.

 

[BBL_Brewer]

There are a couple of online calculators you can use to estimate the cell counts. When you say "Propogator" I assume this is a Wyeast brand propogator? If so, they have a calculaor on the Wyeast web site which is what I use primarily. (I like Wyest Activator Packs) However, Mr. Malty (Jamil Jainasheff) has one too that's pretty nice. Here are some links for ya.....

http://www.wyeastlab.com/hb_pitchrate.cfm

http://www.mrmalty.com/calc/calc.html


Cheers

 

[sjbeerman]

By my estimates by using a propagator with only 25 billion cells will net you around 180 billion without a stir plate or 275 billion with a stir plate in a 1 gallon jug, which would be significantly under pitching. This assumes a 5 gal batch. It seems that propagator packs are not the ideal choice since you are starting at such low cell counts and lagers require significantly higher pitch rates than typical ale brews.

 

[bmantzey]

Well, I did my last lager with less volume of starter using a propagator pack and no, I don't have a stir plate. I'm not very familiar with lagers, obviously. I would assume that at the lower temperature, it would ferment a lot more slowly than an ale would, but the airlock was showing noticeable activity, and there was a good amount of foamy stuff floating on top before I transferred it into the secondary.

It's slowed considerably since I transferred it, but it is still chugging. The OG was around 1.055, it was at 1.03 when I checked it, and the FG should be 1.013-ish. So, it was about half done, but did slow after transferring it. I was a little bit worried about the slowing.

Getting back to the point, I've noticed some calculations do also indicate that I've under pitched. It has me scratching my head a little though, since the brew is indeed fermenting. As long as it is fermenting at a reasonable rate, is there any other reason to ensure my cell count is higher?

I don't know if it matters, but I had plenty of extra ingredients, so I made a mini-brew to yield about .75 gallons and I pitched my starter into that rather than boiling up some DME. I didn't get a gravity reading of the starter, but if my proportions were correct, this brew is supposed to have an OG of ~1.080-1.083. A higher sugar content should give me more yeast activity and more yeast cells in the end, right?

One more question, if I sanitize very carefully, it shouldn't hurt to stick a stir stick in there and stir up the bottom of the jug every now and then, should it? I can only see how this can help the yeast to live long and prosper.

 

[bja]

It's slowed considerably since I transferred it, but it is still chugging. The OG was around 1.055, it was at 1.03 when I checked it, and the FG should be 1.013-ish. So, it was about half done, but did slow after transferring it. I was a little bit worried about the slowing.

You shouldn't transfer it until it reaches FG.

 

[bmantzey]

You shouldn't transfer it until it reaches FG.

Oh shoot! Do you think it'll still ferment to FG after having done this already?

There's a lot of debate over using secondaries, it seems. It almost comes down to what one prefers. My research lead me to the conclusion that a lager shouldn't sit on the trub for long since it's supposed to have a more smooth, less yeast presence in its finish. I didn't realize you're supposed to wait until it's done fermenting.

I'm about to place an order for some more brew supplies. If it's not too late and still possible, I'll add another yeast pack to my order if you would recommend that.

 

[bja]

Oh shoot! Do you think it'll still ferment to FG after having done this already?

There's a lot of debate over using secondaries, it seems. It almost comes down to what one prefers. My research lead me to the conclusion that a lager shouldn't sit on the trub for long since it's supposed to have a more smooth, less yeast presence in its finish. I didn't realize you're supposed to wait until it's done fermenting.

I'm about to place an order for some more brew supplies. If it's not too late and still possible, I'll add another yeast pack to my order if you would recommend that.

At this point I would let it go and see what happens. It should still hit FG, though it'll probably take a bit longer.

 

[40watt]

Well, I did my last lager with less volume of starter using a propagator pack and no, I don't have a stir plate. I'm not very familiar with lagers, obviously. I would assume that at the lower temperature, it would ferment a lot more slowly than an ale would, but the airlock was showing noticeable activity, and there was a good amount of foamy stuff floating on top before I transferred it into the secondary.

It's slowed considerably since I transferred it, but it is still chugging. The OG was around 1.055, it was at 1.03 when I checked it, and the FG should be 1.013-ish. So, it was about half done, but did slow after transferring it. I was a little bit worried about the slowing.

Getting back to the point, I've noticed some calculations do also indicate that I've under pitched. It has me scratching my head a little though, since the brew is indeed fermenting. As long as it is fermenting at a reasonable rate, is there any other reason to ensure my cell count is higher?

I don't know if it matters, but I had plenty of extra ingredients, so I made a mini-brew to yield about .75 gallons and I pitched my starter into that rather than boiling up some DME. I didn't get a gravity reading of the starter, but if my proportions were correct, this brew is supposed to have an OG of ~1.080-1.083. A higher sugar content should give me more yeast activity and more yeast cells in the end, right?

One more question, if I sanitize very carefully, it shouldn't hurt to stick a stir stick in there and stir up the bottom of the jug every now and then, should it? I can only see how this can help the yeast to live long and prosper.

After a lot of reading, it seems that the problem with under pitching a lager is not a matter of will it ferment, but a matter of lager yeast producing an increased amount of off flavors under less than perfect conditions.

Also, yeah I'm confused as to why you would transfer before primary fermentation is over.

 

[BBL_Brewer]

One more question, if I sanitize very carefully, it shouldn't hurt to stick a stir stick in there and stir up the bottom of the jug every now and then, should it? I can only see how this can help the yeast to live long and prosper.

If you want to increase your yeast production a little bit, just swirl the jug around every once in a while to resuspend the yeast. You could do the stir stick thing too though as long as your sanitation is good. I highly reccomend you build a stir plate.....or buy a cheap one if you're not comfotable building one.


Cheers

 

[bmantzey]

Yeah, I've heard some people say, "Why the heck would you do that?" and I've heard others give very logical reasons. It came down to, I decided to do it to end up with a cleaner beer. I also saw in someone's signature, "I use secondaries." That indicated to me some sarcasm relating to the debate of whether or not a secondary is necessary. *shrug*

I just wish I would have waited until it reached its FG before transferring it.

 

[BBL_Brewer]

Yeah, I've heard some people say, "Why the heck would you do that?" and I've heard others give very logical reasons. It came down to, I decided to do it to end up with a cleaner beer. I also saw in someone's signature, "I use secondaries." That indicated to me some sarcasm relating to the debate of whether or not a secondary is necessary. *shrug*

I just wish I would have waited until it reached its FG before transferring it.

RDWHAHB - Relax, don't worry, have a home brew....

 

[bmantzey]

I just found a noteworthy quote from Jonh Palmer's website "How To Brew", referring to lager's:

...you should rack to a secondary when the krausen has started to fall back in.

http://www.howtobrew.com/section1/chapter10-5.html

I, unfortunately, didn't know this at the time I transferred it to the secondary. Heck, I didn't even know it was called "Krausen", and there was plenty of this stuff floating on the top when I did transfer it. I'm sincerely hoping it turns out okay. I hope the yeast hasn't deactivated or anything. I've been fermenting at around 47°, maybe I should bring it up closer to the 50°-52 mark to help speed it up?

So much to learn! <3 it!!