Starter question - enough time to decant?

[imtrashed]

I'll be brewing the AHS Imperial Robust Porter tonight with expected OG of 1.090. I smacked my Pacman yeast pack on Tuesday night and started my yeast starter on Wednesday night. Anxious to get a bigger starter, I added another 3 cups of starter wort on top of it last night. It's up to about 1.2 Liters now and still fermenting out. Some starter questions:

Should I let it continue to ferment until tonight and pitch the entire 1.2 Liters? Will the 1.2 Liters of extra light DME affect my porter all that much?

Should I get it into the fridge today and hope that it settles out some and decant some of the liquid off?

What is typically the amount of time a 500mL starter needs to ferment out completely? What is typically the amount of time it takes for a starter in the fridge to settle out completely, so I can decant the beer off without dumping too much good yeast?

Any input is very much appreciated. I don't post much on here, but would love some guidance. Just getting started using starters. Loved the way my last Kolsch blew through fermentation, even at 52 - 58 degrees.

 

[WrongCoastBrewery]

First off, I would suggest checking out mrmalty.com and look at the yeast pitching rate calculator. Currently you are underpitching by a ton. With three smack packs, your current amount is correct, but I am assuming you are only using one. I also assume you dont have a stir plate. With one smack pack and intermittent shaking, you would need about 5L of starter. You are brewing a BIG beer and you will need all the yeasties you can get to ferment that bad boy down.

No, the LME will not affect the beer. Most people directly pitch, but about 24hrs is all you would need to have it settle out prior to decanting. I would highly suggest doing a bigger starter. Your Kolsch that you mentioned blew through fermentation sure, but this bad boy at just a little over a 1L starter will be taking some time to get to full fermentation.

 

[MikeSzwaya]

+1. I'm assuming you are brewing a 5 gallon batch. Even so, you're drastically underpitching a 1.090 beer by at least half.

At this point, 1.2L of a LME starter would have little impact on a high gravity porter. Lighter beers, perhaps. But I highly doubt it will affect a beer this dark.

My smaller starters generally take a day. If I have to make a second step up, I give it a couple more. In general, I start a week in advance.

I would recommend at least 48 hours, preferably 72, for a yeast starter to properly go dormant and settle out in the fridge. In rushing the process, you run the risk of decanting off some of the less flocculent yeast that will help your beer attenuate further.

 

[imtrashed]

Thanks guys. So, now I am in a quandry. I wanted to have a brew session tonight and then another on Sunday. I only created a starter for my Sunday brew session this morning, but it's only a pale ale with a 1.059 OG.

What do you all think I should do? Should I brew the pale ale tonight and pitch that starter tonight, and then hold off on the porter until Sunday? The problem is that I don't have any DME left to step up the porter starter. I guess I could use some of the LME that came with the porter ingredient kit. Is that a good course of action? Or do I just pitch the porter starter tonight as planned and just work with a slow fermentation. I plan to let this one sit in the primary for several weeks anyway.

 

[MikeSzwaya]

There's some things you can do and some you probably shouldn't.
Given your current yeast situation, I'd give up on the porter this weekend. It's not as simple as underpitching and hoping that it will finish out in time. You could leave it on the primary for months and it may not ever finish. We're asking a lot of too little yeast. Odds are that in a couple months, you'd need to repitch more yeast. I'm not guaranteeing that this will happen, I'm just saying that this is a pretty common consequence of underpitching. For a time consuming and expensive beer, it's up to you whether or not you want to proceed.
Your 1.2L starter is good for that pale ale batch. I'd brew that this weekend. Oxygenate well, use nutrients, and be very clean.
Next weekend, your pale ale should be done. You can reuse 3/4 cup that yeast slurry to pitch into the porter. That's close to what it needs.
If you absolutely, positively have to brew twice this weekend, look into dry yeast. 18 grams of properly rehydrated dry yeast should finish a 1.090 beer.

 

[imtrashed]

Some more back story... the starter that I have going for my porter uses the Rogue Pacman yeast and I really wanted to see how that did and the flavors that it would produce.

I found a LHBS where I can pick up some additional yeast tonight. They have Wyeast, Saflager, Danstar. What do you think I should pitch with my Pacman starter?

Should I just get some S-04 or Nottingham and throw that in with the starter that I made for my porter? Should I pick up a smack pack and throw that in when I pitch my porter starter?

I was REALLY hoping to use the slurry from this porter for an upcoming imperial stout. Should I use the S-04 or Nottingham to try to keep it relatively neutral?

 

[imtrashed]

Update... I found out that a brew pub near my home doubles as a homebrew supply store. They're going to set aside some Nottingham for me to pick up on the way home from work. I appreciate all the input/advice. Have already learned a lot from being on these boards and was definitely nervous (panicking) when I realized that my starter might not be ready for this high gravity beer. I hate to have to throw 2 different yeasts at this porter, since it's the first time brewing it and I wanted to see how it came out, but I also want to make sure I'm not wasting 5 gallons of goodness.

If anyone is still reading this... can anyone comment on how the slurry might turn out from this batch? Will one yeast take over and be more dominant in the slurry, in case I want to repitch it? I know the Nottingham will fall out pretty quickly and have no experience with the Pacman. I want to throw the resulting slurry on an even bigger stout in a few weeks.

 

[MikeSzwaya]

I think you're heading in the right direction. But there's a couple things worth commenting on.

Any of the dry yeast nowadays are good. I'll use them in a pinch. Just make sure to properly rehydrate them. Aim for as neutral a yeast as possible. The ferment of a big porter is already going to generate a lot of flavor compounds. Using fruity/estery yeasts (like the English ones) can be a little excessive. The Safale S-05 may be a better choice. English ale yeasts are also slightly less attenuative. Comparatively, the S-05 may help dry the beer out a little more.

I don't think that using the 2 yeasts together will have any significant impact on the final flavor. Like I said, you're brewing a big porter. There's plenty of flavor already.

As far as the yeast to use - 5 gal. of 1.090 beer ideally needs 340 billion cells to ferment. Your smack pack and starter just generated about 170 B cells, leaving you short about 170 B cells. According to Fermentis (Safale makers) the 11.5 gram dry yeast packets contain at least 69 billion cells each. 2 packs plus your starter should give you close to the required 340 billion cells for that porter. Comparatively, the smack packs contain about 100 billion cells. Going slightly over is better than under.

The last thing I would do is caution against reusing this yeast slurry. The general guideline is to avoid reusing yeast from beers greater than 1.060. If your 1.090 beer ferments down to 1.020 (at 77% attenuation), you'll have a solid 10.4% abv beer. The fermentation process and the ending alcohol content puts a substantial amount of stress on yeast, leaving it in pretty poor shape. Asking it to saddle up again and ferment another big beer is a tall order. You can do it (the Belgians do it all the time), but make sure to oxygenate when you pitch and preferably again 18-24 hours later. This will provide the yeast enough oxygen to build up a strong cell wall to withstand the high alcohol content.

As a side note, I'm not picking on you. Really. Understanding and managing yeast correctly is one of the harder tasks in brewing. But if you get it right, it really can move your beer from 'good' to 'great'. Good luck this weekend.

 

[imtrashed]

I totally and sincerely appreciate all the feedback. It's the only way to get better. Thanks for taking the time.

 

[imtrashed]

So, I ended up brewing the pale ale on Friday night with the 500 mL starter I made that morning and an additional packet of Nottingham. Fermentation started no problem and seems to be moving along fine.

I ended up stepping up the porter starter to 2 Liters and pitched it on Sunday along with a packet of Nottingham. Fermentation started in about 2 hours! That's a personal best for me. This morning still shows great airlock activity, so I hope that it continues to ferment down to a low FG. OG was only about 1.081 instead of the 1.090 I was hoping for.