Author Topic: My first yeast starter - questions!  (Read 7407 times)

Offline jivetyrant

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My first yeast starter - questions!
« on: February 13, 2011, 07:04:35 AM »
So I'm planning on doing an Imperial Stout today, target ABV of 10.7% with an OG of 1.104, FG 1.024.  It was recommended that I use some more advanced brewing techniques than I have tried previously, including preparing a yeast starter.  The gentleman at my local homebrew supply store told me that the best way to prepare a starter is to combine about 4 cups of water with 1 cup of DME, boil for 10-15 minutes and cool to pitching temp. (75ish)  Add 1/8 tsp of yeast nutrient and pitch my yeast, in this case 1 vial of WLP001, white labs california ale then shake thoroughly to aerate.  The gear he recommended was a 2000ml flask and a foam stopper, both of which I purchased.  His last piece of advice was to give it a quick shake several times a day to keep the yeast in suspension as it would promote more rapid metabolism of the sugars in the starter.  He told me to prep it a day or two ahead of time and to pour off and clear liquid that formed on top of the starter as I would not want it in my carboy.

Well, I followed his advice to the letter but my starter isn't doing a hell of a lot!  it's got a thin layer of bubbles but isn't as vigorous as I would have expected.  I started it yesterday at about 11am, I'm planning on brewing tonight at about 5pm, perhaps earlier if possible.  Is my timeline realistic?  Was my starter prepared correctly?  Am I just expecting more activity from my starter than is normal?  Halp!

Offline majorvices

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Re: My first yeast starter - questions!
« Reply #1 on: February 13, 2011, 07:18:59 AM »
You don't always get a lot of foam on a yeast starter. Just keep swirling it every chance you get and don't worry.

FWIW you are doing great by making a starter, but really, you will have better beer making a starter for every beer, not just high gravity. Go with what you have today, but next time consult http://www.mrmalty.com/calc/calc.html to see exactly how big a starter you need for every batch.
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Offline jivetyrant

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Re: My first yeast starter - questions!
« Reply #2 on: February 13, 2011, 07:47:00 AM »
Wow, that's a damn handy tool you've got there!  Very cool stuff. :)

Offline denny

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Re: My first yeast starter - questions!
« Reply #3 on: February 13, 2011, 08:10:50 AM »
If you're not using a stir plate, I'd recommend making your starter at least 3-4 days in advance. 
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Offline jivetyrant

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Re: My first yeast starter - questions!
« Reply #4 on: February 13, 2011, 08:22:30 AM »
I was afraid of that, guess I'm not brewing today :p

Offline hokerer

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Re: My first yeast starter - questions!
« Reply #5 on: February 13, 2011, 09:45:39 AM »
And, for a 1.104 OG, you're going to want a bigger starter than just one quart.
Joe

Offline jivetyrant

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Re: My first yeast starter - questions!
« Reply #6 on: February 13, 2011, 10:17:09 AM »
should I boil and cool more water then just add it to the existing starter?  How much?

Should I also use more DME?  How much?

Should I spring for another vial of yeast?

Offline denny

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Re: My first yeast starter - questions!
« Reply #7 on: February 13, 2011, 10:32:39 AM »
should I boil and cool more water then just add it to the existing starter?  How much?

Should I also use more DME?  How much?

Should I spring for another vial of yeast?

You need to use both more DME and more water.  More yeast will be helpful, too.  For the definitive answers, though, please see mrmalty.com.
Life begins at 60.....1.060, that is!

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Offline punatic

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Re: My first yeast starter - questions!
« Reply #8 on: February 13, 2011, 04:38:12 PM »
prepare a starter is to combine about 4 cups of water with 1 cup of DME, boil for 10-15 minutes and cool to pitching temp.

Well, I followed his advice to the letter but my starter isn't doing a hell of a lot! 

4 cups of water plus 1 cup of DME gave your starter wort a original gravity of 1.120 
BEFORE you boiled it.
Boiling removed water and increased the original gravity of the starter wort even higher.

I suspect your starter yeast is suffering from high gravity shock.
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Offline majorvices

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Re: My first yeast starter - questions!
« Reply #9 on: February 13, 2011, 06:06:00 PM »
10-12 oz of DME to 1 gallon or 4L of water will give you between 1.030 and 1.040 OG starter. For a 2L or 1/2 gallon starter use 5-6oz DME. That's what is easiest for me to remember.  You definitely don't want the starter stronger than 1.040 or so. You want to grow yeast, not scare the hell out of them, and high gravity worts cause lots of stress. In layman's terms its like having a nice salad as opposed to being involved in a hotdog eating contest.  ;)
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Offline tschmidlin

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Re: My first yeast starter - questions!
« Reply #10 on: February 13, 2011, 06:30:40 PM »
prepare a starter is to combine about 4 cups of water with 1 cup of DME, boil for 10-15 minutes and cool to pitching temp.

Well, I followed his advice to the letter but my starter isn't doing a hell of a lot!

4 cups of water plus 1 cup of DME gave your starter wort a original gravity of 1.120 
BEFORE you boiled it.
Boiling removed water and increased the original gravity of the starter wort even higher.

I suspect your starter yeast is suffering from high gravity shock.
What numbers are you using to calculate this?  Working backwards, it looks like you're estimating a cup of DME to weight 11 oz or the water volume is off by half.  Granulated sugar is closer to 7 oz, in my experience a cup of DME is less, about 5.5 - 6 oz (there's variability).  I figure this starter would be about 1.065 pre-boil, more after.  It's still too high though.  A half cup of DME in a quart would be better for the starter.

But weighing is better than volume measurements, I use DME equaling 8-10% of the water weight.
Tom Schmidlin

Offline punatic

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Re: My first yeast starter - questions!
« Reply #11 on: February 13, 2011, 07:10:42 PM »

prepare a starter is to combine about 4 cups of water with 1 cup of DME, boil for 10-15 minutes and cool to pitching temp.

Well, I followed his advice to the letter but my starter isn't doing a hell of a lot!

4 cups of water plus 1 cup of DME gave your starter wort a original gravity of 1.120 
BEFORE you boiled it.
Boiling removed water and increased the original gravity of the starter wort even higher.

I suspect your starter yeast is suffering from high gravity shock.
What numbers are you using to calculate this?  Working backwards, it looks like you're estimating a cup of DME to weight 11 oz or the water volume is off by half.  Granulated sugar is closer to 7 oz, in my experience a cup of DME is less, about 5.5 - 6 oz (there's variability).  I figure this starter would be about 1.065 pre-boil, more after.  It's still too high though.  A half cup of DME in a quart would be better for the starter.

But weighing is better than volume measurements, I use DME equaling 8-10% of the water weight.

Pre-boil Specific Gravity calculations:

Densities measured at STP
Water has a density of 1.000 g/mL
DME has a density of 1.6 g/mL
1 cup = 8 fluid oz.
1 fluid ounce = 29.57 mL

1 cup DME = 1cup x 8oz/cup x 29.57mL/oz x 1.6g/mL = 378.5g DME 

4 cups water = 4cup x 8oz/cup x 29.57mL/oz x 1.0g/mL = 946.2g water

5 cups solution = 378.5g DME + 946.2g water = 1324.7g wort

5 cups solution = 5 cups x 8oz/cup x 29.57mL/oz = 1182.8 mL wort

Density = 1324.7g / 1182.8mL = 1.120g/mL

Specific Gravity = (1.120g/mL) / (1.000g/mL) = 1.120

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Offline jivetyrant

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Re: My first yeast starter - questions!
« Reply #12 on: February 13, 2011, 07:18:34 PM »
I have another question!

My starter is no longer producing much in the way of bubbles and there is a yeast cake that has formed in the bottom of the flask.  Shaking the flask yields much less vigorous foaming than before and the yeast cake does not break up fully, it looks somewhat chunky now.  Does this mean that my starter is "done," so to speak?  If so, how can I store it until I'm ready to brew? (probably in the next couple of days)  Can I just stash it in the fridge and take it out 4 or so hours before brewing, or am I now on a timeline before it goes south?

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Re: My first yeast starter - questions!
« Reply #13 on: February 13, 2011, 08:13:07 PM »
Stashing it in the fridge is the right thing to do.  It also has the added advantage that, shortly before you're ready to use it, you can decant off the spent "beer" and just pitch the yeast.  The time in the fridge gets the yeast to settle to the bottom.
Joe

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Re: My first yeast starter - questions!
« Reply #14 on: February 13, 2011, 08:18:59 PM »
I think the sediment you are seeing is mostly trub.  Yeast sediment tends to be "dusty" when disturbed.  The yeast often appears as a thin layer of lighter colored sediment on top of the darker trub sediment on the bottom of the fermentation vessel.

If it were me, I would make a new yeast starter from scratch, using 100g of DME to 1 liter of water (1/4 cup DME to 1 quart of water) and pitch a new yeast culture.  
Or better still 1/2 cup DME to 1/2 gallon of water.

IMHO - Replacing a starter is less expensive than replacing a batch of beer that has off-flavors.

If you should decide to use what you have, storing it in a dark, room-temperature place for a day or two is good.  Storing it in the fridge will cause a longer lag time when you pitch it into the wort.  For more than a day or two - the fridge is the way to go.
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