Author Topic: Basic Yeast Questions  (Read 4222 times)

Offline HoosierBrew

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Re: Basic Yeast Questions
« Reply #15 on: June 09, 2013, 06:48:28 PM »
What about the Hefeweizen and Belgian idea of intentionally under pitching to produce the esters?
+1.  Always my understanding too.
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Offline denny

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Re: Basic Yeast Questions
« Reply #16 on: June 10, 2013, 09:35:11 AM »
What about the Hefeweizen and Belgian idea of intentionally under pitching to produce the esters?

My understanding is that these strains do [produce more esters by underpitching, but the whole issue is so nebulous I wouldn't say for certain.
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Offline a10t2

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Re: Basic Yeast Questions
« Reply #17 on: June 10, 2013, 10:22:35 AM »
What about the Hefeweizen and Belgian idea of intentionally under pitching to produce the esters?

I've never seen a controlled study suggesting that's actually the case. (Actually, I'm getting ready to start one with a Belgian strain, but I don't have an HPLC, so it will be totally subjective.)
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Offline klickitat jim

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Re: Basic Yeast Questions
« Reply #18 on: June 10, 2013, 12:20:19 PM »
It's sounding like these may be basic yeast question but there are few basic yeast answers. I will wrap my mind around this eventually though.

Offline denny

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Re: Basic Yeast Questions
« Reply #19 on: June 10, 2013, 12:22:58 PM »
What about the Hefeweizen and Belgian idea of intentionally under pitching to produce the esters?

I've never seen a controlled study suggesting that's actually the case.

Agreed.  AFAIK, it's anecdotal.
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Offline klickitat jim

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Re: Basic Yeast Questions
« Reply #20 on: June 10, 2013, 02:26:26 PM »
I'm way green to the hobby/science but it seems to me that very little of this is settled law.

Offline joe_feist

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Re: Basic Yeast Questions
« Reply #21 on: June 10, 2013, 03:05:14 PM »
I think it's as much art as science, so I'd agree it's not settled law. I seem to run into as many different opinions as there are posters out there (and books, too).

It's pretty fun, really, to work through this and see what happens. We all have different set-ups (equipment), recipes, yeasts, environments, yadda, yadda, yadda...

So, I believe there's general agreement that yeast used the fresher the better. The merits of under pitching versus over pitching seems to be a matter of debate. I will say that I thought the yeast strains themselves were responsible for the unique flavors of weizens versus deliberately under pitching. I don't know if that's right or wrong, I'm just saying I never considered that as a variable. Something to think about.
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Offline klickitat jim

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Re: Basic Yeast Questions
« Reply #22 on: June 10, 2013, 03:38:37 PM »
I have no doubt that I am at the beginning of the learning curve. I think I have the basics (do this or you won't make decent beer) down pat. But as far as the rest? Just getting started.

I've said this before but, I think brewing is one of those things where sometimes you read something as fact and it ain't so. Doctor Palmers first edition HTB for example. Its a great starting point, but a lot of the deep stuff is up for discussing. That said, he knows way way more than me.

Yeast, they are our friends. Be kind and they will reward you.

Offline denny

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Re: Basic Yeast Questions
« Reply #23 on: June 10, 2013, 03:49:56 PM »
Jim, I think the key is read a lot.  When you read something that seems to make sense from a person who seems to know what (s)he's talking about, try it and see if it works for you.  Repeat often.
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Offline klickitat jim

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Re: Basic Yeast Questions
« Reply #24 on: June 10, 2013, 04:27:22 PM »
Bingo! Well said.

I also think that years brewing doesn't always equate to experience expertise or knowledge. In my profession I know several with multiple years of repeating the same thing they learned the first six months. We call them retired on duty lol.

Thanks entirely to this forum, Denny in particular,  I feel I've learned as much as a vet home brewer in just a couple months.

Offline ynotbrusum

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Re: Basic Yeast Questions
« Reply #25 on: June 10, 2013, 07:39:02 PM »
Bingo! Well said.

Thanks entirely to this forum, Denny in particular,  I feel I've learned as much as a vet home brewer in just a couple months.

It allows you to learn from the mistakes of others, because Lord knows I make some anyway, I might as well miss a few on the way!  Some really good info here, for sure....
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Offline klickitat jim

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Re: Basic Yeast Questions
« Reply #26 on: June 10, 2013, 07:44:49 PM »
Totally!  I remember about 1990 a guy i worked with home brewed. His stuff rocked. I thought. But wow things have changed

Offline aschecte

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Re: Basic Yeast Questions
« Reply #27 on: June 10, 2013, 09:37:36 PM »
I think I've been under pitching. As you know I bought a couple stir plates recently and I'm learning about that. I bought the Mr Malty app and figured out how to work that. I've watched a few wyeast and white labs videos. ..

1. Lets say I run a 2000ml starter for 24 hrs, then put the flask in the fridge to settle the yeast. How long can it sit in the fridge before decant and pitch? Would 3 or 4 days have much effect?

2. When washing and repitching from a previous brew, how do you estimate and measure how much of that to pitch. A low tech method would be awesome. How long can the washed yeast last in the fridge? Can you use the same viability rates as the smack packs, like about 30% loss per month?

3. Generally speaking, how do ester and fusel production relate to fermentor temp and pitch rate?

I'm asking these questions to verify my understanding. Here's what I think.

1. I think a starter would be just fine in the fridge for a few days, but after a week or so you begin losing viability.

2. I think if you wash a yeast cake right away and keep it in the fridge, it's good for a few days before viability loss starts. I personally wouldn't use it as-is past a month. I think for an <1.060 ale I would use a half cup slurry. Double for a lager or high gravity ale.

3. I think that low pitch rate encourages growth and therefore less esters and more off flavors. High pitch rate increases ester, decreases off flavor except if your over pitch leads to Autolysis. I think fermenting at the low end of the yeasts temp range reduces esters but risks off flavors from poor fermentation. Fermenting at the high end increases esters but risks high fusel production.

Am I on track?  Set me straight please
On part 1 I think your probably pretty solid though I make my starters the day before I brew which is usually on Sunday so mid day Friday I begin my starter and by Saturday night it's in the keezer dropping that yeast from suspension on Sunday decant and pitch. I think your fine from everything I have read for a few days and your probably on target for that 1 week loss of viability.

#2 I don't save cakes though others do and could give better advice though I do rack fresh wort onto a cake so it a bit of a PITA as my brew partner is kegging a beer during the last hour of brewing ( sanitizing the keg racking cane hoses etc and the actual transfer) we usually leave just enough beer to keep the cake barely covered and then cover the carboy back up with a sanitized bung and airlock. once the fresh wort is chilled to temp onto the cake the fresh wort goes. I have read of people collecting the cake and using for up to a week.
 
#3 and I could be way off but I think I'm on target a low pitch rate causes more esters as they are a by product of the growth phase and a low pitch rate can also cause off flavors. A high pitch rate will cause off flavors fusel alcohol and is IMHO worse than under pitching. I would recommend doing neither pitch the proper amount or if reusing a cake try to match the OG of the previous beer to the new OG as close as possible as then you are only bypassing the reproductive and growth phase and just going straight into straight up chomping on sugar phase.

hope that helps but if anyone with more experience disagrees please also set me straight.
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Offline denny

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Re: Basic Yeast Questions
« Reply #28 on: June 11, 2013, 10:07:56 AM »
I could be way off but I think I'm on target a low pitch rate causes more esters as they are a by product of the growth phase and a low pitch rate can also cause off flavors.

Take another look at the info from Clayton Cone and Neva Parker in this thread.  There's persuasive evidence that higher pitch rates create more esters.
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Offline aschecte

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Re: Basic Yeast Questions
« Reply #29 on: June 11, 2013, 10:51:16 AM »
I could be way off but I think I'm on target a low pitch rate causes more esters as they are a by product of the growth phase and a low pitch rate can also cause off flavors.

Take another look at the info from Clayton Cone and Neva Parker in this thread.  There's persuasive evidence that higher pitch rates create more esters.
Denny as you know I'm kinda new here and not to sound like an idiot but I don't see anyone with those names in this thread....... are you using their real names? it sounds like they are... I can't see that is there a option for this somewhere if this is the case ?
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