Homebrewers Association | AHA Forum

General Category => General Homebrew Discussion => Topic started by: lees_brew on February 13, 2011, 02:53:43 AM

Title: how do you make a yeast starter?
Post by: lees_brew on February 13, 2011, 02:53:43 AM
I have looked and not had any luck.  How do you make a yeast starter? Is it done with dry yeast or liquid yeast? Also go you harvest yeast? This is another thing I have know idea about but would like to.

Once again
Thanks
Lee
Title: Re: how do you make a yeast starter?
Post by: tygo on February 13, 2011, 03:06:00 AM
For a starter, put 100g of DME in 1L of water (or 200 g in 2L, etc), boil it for 10 minutes or so, add some yeast nutrient if desired.  Chill it down to 70F in a water bath and put it in a suitable container (a sanitized gallon water jug works well).  Pitch your yeast into it and then shake it up.  Then let it ferment out.



Title: Re: how do you make a yeast starter?
Post by: maxieboy on February 13, 2011, 03:57:08 PM
For a starter, put 100g of DME in 1L of water (or 200 g in 2L, etc), boil it for 10 minutes or so, add some yeast nutrient if desired.  Chill it down to 70F in a water bath and put it in a suitable container (a sanitized gallon water jug works well).  Pitch your yeast into it and then shake it up.  Then let it ferment out.

This is for liquid yeast. Starters not recommended for dry.
Title: Re: how do you make a yeast starter?
Post by: punatic on February 13, 2011, 04:14:23 PM
For a starter, put 100g of DME in 1L of water (or 200 g in 2L, etc), boil it for 10 minutes or so, add some yeast nutrient if desired.  Chill it down to 70F in a water bath and put it in a suitable container (a sanitized gallon water jug works well).  Pitch your yeast into it and then shake it up.  Then let it ferment out.


That will give you an original gravity near 1.100.  That's a bit high for a yeast starter, isn't it?
Title: Re: how do you make a yeast starter?
Post by: jamminbrew on February 13, 2011, 04:41:50 PM
I use  1/4cup DME  to 2 qt water, it has worked fine for me.
Title: Re: how do you make a yeast starter?
Post by: denny on February 13, 2011, 04:43:58 PM
For a starter, put 100g of DME in 1L of water (or 200 g in 2L, etc), boil it for 10 minutes or so, add some yeast nutrient if desired.  Chill it down to 70F in a water bath and put it in a suitable container (a sanitized gallon water jug works well).  Pitch your yeast into it and then shake it up.  Then let it ferment out.


That will give you an original gravity near 1.100.  That's a bit high for a yeast starter, isn't it?


About 3-4 times too high!
Title: Re: how do you make a yeast starter?
Post by: gmwren on February 13, 2011, 05:33:04 PM
100g to 1L is the Wyeast recipe for 1.040. I get good results with 65g to 1L for an SOG in the mid twenties. Supposedly higher gravity can cause the yeast to work harder producing alcohol instead of biomass. Without an accurate means of cell count, I can only observe the slurry thickness appears the same between starters of 1.040 and 1.025.
Title: Re: how do you make a yeast starter?
Post by: maxieboy on February 13, 2011, 05:42:39 PM
For a starter, put 100g of DME in 1L of water (or 200 g in 2L, etc), boil it for 10 minutes or so, add some yeast nutrient if desired.  Chill it down to 70F in a water bath and put it in a suitable container (a sanitized gallon water jug works well).  Pitch your yeast into it and then shake it up.  Then let it ferment out.


That will give you an original gravity near 1.100.  That's a bit high for a yeast starter, isn't it?

100g = 3.53 oz.
3 oz in 1L gives approx. 1.030
3.53 in 1L gives approx. 1.040
1.030-1.040 is the generally accepted range for yeast starter gravity.


Early in the morn for ya?
Title: Re: how do you make a yeast starter?
Post by: kgs on February 13, 2011, 06:05:31 PM
The Homebrewopedia offers a yeast starter recipe (http://wiki.homebrewersassociation.org/YeastStarter ). That said... several small observations:

* Its recipe for a yeast starter recommends 1 cup DME to a quart of water. Using Beersmith, if I go with 1 cup DME weighing .4 lbs, that works out to 1.071 OG -- pretty high. I can get to 1.045 OG if I assume 1 cup DME = .25 ounces.

* Providing weight for the DME in this recipe (in both US and metric) might encourage new brewers to make critical measurements by weight, not volume. DME is a hard thing to estimate by volume, especially for such a small amount of wort. I'm not saying don't list a volume measurement... just suggesting someone with credibility might want to add weight measurements to this fairly important recipe.

* Some interesting SEO: a Google search for "making yeast starter" or "yeast starter" doesn't yield a link to anything on the homebrewersassociation.org domain for the first twenty results--even though most of Google's results for these search phrases are related to brewing. If I force a site search ("making yeast starter site:homebrewersassociation.org"), it's the 7th result. If I remove the verb "making" and force a site search, it's the third result. I have to force a subdomain site search to make it the third result  ("yeast starter site:wiki.homebrewersassociation.org"). Shouldn't the AHA's recipe for yeast starter be *the* first result in any general Google search?

Now back to the work stuff I've been avoiding...
Title: Re: how do you make a yeast starter?
Post by: denny on February 13, 2011, 06:10:05 PM
Always weigh the DME for a starter.  Volume measurements can give widely different weights.
Title: Re: how do you make a yeast starter?
Post by: maxieboy on February 13, 2011, 06:16:07 PM
For a starter, put 100g of DME in 1L of water (or 200 g in 2L, etc), boil it for 10 minutes or so, add some yeast nutrient if desired.  Chill it down to 70F in a water bath and put it in a suitable container (a sanitized gallon water jug works well).  Pitch your yeast into it and then shake it up.  Then let it ferment out.


That will give you an original gravity near 1.100.  That's a bit high for a yeast starter, isn't it?


About 3-4 times too high!

1.100 is obviously too high for starter gravity wort, but tygo's info is correct...
Title: Re: how do you make a yeast starter?
Post by: maxieboy on February 13, 2011, 06:17:23 PM
Always weigh the DME for a starter.  Volume measurements can give widely different weights.

+1
Title: Re: how do you make a yeast starter?
Post by: denny on February 13, 2011, 07:20:07 PM
1.100 is obviously too high for starter gravity wort, but tygo's info is correct...

Agreed.
Title: Re: how do you make a yeast starter?
Post by: punatic on February 13, 2011, 07:20:34 PM
Oops... I went back and did some math.  My "before my Sunday morning coffee" estimation of a starter O.G. of 1.100 was way off.  100 g of solids dissolved in a 1 L solution does have a Specific Gravity of 1.100, but that's not whats going on here...

Assume:
Densities measured at STP
Water has a density of 1.0 g/mL
DME has a density of 1.6 g/mL
100 g of DME = 62.5 mL

If you add 100 g of DME to 1000 mL (1L) of water the mass of the solution is now 1100 g.
The volume of the solution is now 1062.5 mL.
The density of the new solution is 1100 g /1062.5 mL  = 1.0353 g/mL

Specific Gravity is the (unitless) ratio of the density of a solution divided by the density of water:
Specific Gravity = (1.0353 g/mL) / (1.0000 g/mL) = 1.0353

If 10% of the volume of water is lost during the 10 minute boil (assume no solids are lost during the boil)
The after-boil volume is 1062.5 mL - 106.2 mL = 956.3 mL
The after-boil mass of the solution is  1100 g - 106.2 g = 993.8 g
After-boil density = 993.8 g / 956.3 mL = 1.0392 g/mL

After-boil Specific Gravity = (1.0392 g/mL) / (1.0000 g/mL) = 1.0392

Which is a good Specific Gravity for a beer yeast starter



Title: Re: how do you make a yeast starter?
Post by: tygo on February 13, 2011, 08:28:47 PM
Which is a good Specific Gravity for a beer yeast starter

Right, that's what I was saying.  ;D
Title: Re: how do you make a yeast starter?
Post by: punatic on February 13, 2011, 08:33:22 PM
Which is a good Specific Gravity for a beer yeast starter

Right, that's what I was saying.  ;D

Hey, the boards were a bit slow this morning, so I figured I'd stir it up a bit...   ;)
Title: Re: how do you make a yeast starter?
Post by: kgs on February 13, 2011, 09:04:41 PM

If 10% of the volume of water is lost during the 10 minute boil (assume no solids are lost during the boil) ...

That calculation caught my eye. A ten minute boil is a long time for a small amount of liquid.  I brought a quart of water to a boil in a two-quart saucepan, uncovered the pan, and set the timer, then turned off the flame and poured out the water as soon as ten minutes were reached. The water had lost 50% of its volume.

Obviously, there are easy fixes: add preboiled water to restore the volume. Start with more than a quart of water. Cover the pan for part of the boil. Palmer recommends, "Put the lid on the pan for the last couple minutes" -- I do that anyway, to steam down any wort crystals and to kill the bugs -- and that would also help reduce loss. 

But the key is to know what your target OG should be for your starter and focus on that, and I can honestly say I haven't been doing that for starters (why, I don't know, since I am almost obsessive about hitting my OG for my beer).

Good thread!

Title: Re: how do you make a yeast starter?
Post by: maxieboy on February 13, 2011, 09:20:14 PM
Whew! I'm glad that's settled... ;D
Title: Re: how do you make a yeast starter?
Post by: denny on February 13, 2011, 09:35:24 PM

That calculation caught my eye. A ten minute boil is a long time for a small amount of liquid.  I brought a quart of water to a boil in a two-quart saucepan, uncovered the pan, and set the timer, then turned off the flame and poured out the water as soon as ten minutes were reached. The water had lost 50% of its volume.



Very interesting.  I boil for 10 min. also.  I start with 9-10 cups and end up right around 2 qt.  some loss, but nowhere near 50%.
Title: Re: how do you make a yeast starter?
Post by: punatic on February 13, 2011, 10:41:07 PM
Is boiling the starter wort for sterilization or hot break, or neither/both/something else?

I used 10% cause it's easy and in the ballpark.
Title: Re: how do you make a yeast starter?
Post by: kgs on February 14, 2011, 01:18:03 AM

That calculation caught my eye. A ten minute boil is a long time for a small amount of liquid.  I brought a quart of water to a boil in a two-quart saucepan, uncovered the pan, and set the timer, then turned off the flame and poured out the water as soon as ten minutes were reached. The water had lost 50% of its volume.



Very interesting.  I boil for 10 min. also.  I start with 9-10 cups and end up right around 2 qt.  some loss, but nowhere near 50%.

I assume an uncovered pan, and a rolling boil, with the ten minutes starting at the beginning of the boil? I was surprised by my boil-off results myself, but there it was. I'll test it again for repeatability. As tests go, it's an easy one :) This time, I'll wear a lab coat.

I wonder if wort boils off more slowly than water. I wonder if I'm over-thinking this and should RDWHAHB (actually I am!).
Title: Re: how do you make a yeast starter?
Post by: tygo on February 14, 2011, 03:18:43 AM
I generally boil my starters in an Erlenmeyer flask which helps keep the boil off down.

I don't usually wear a lab coat though.  ;)
Title: Re: how do you make a yeast starter?
Post by: oscarvan on February 14, 2011, 01:25:23 PM
(http://www.clipartguide.com/_named_clipart_images/0511-0908-2808-1650_Wacky_Science_Teacher_Doing_a_Lab_Experiment_clipart_image.jpg)
Title: Re: how do you make a yeast starter?
Post by: punatic on February 14, 2011, 03:58:15 PM
(http://www.clipartguide.com/_named_clipart_images/0511-0908-2808-1650_Wacky_Science_Teacher_Doing_a_Lab_Experiment_clipart_image.jpg)

Give him some chin whiskers and he looks a lot like Tom... ;)
Title: Re: how do you make a yeast starter?
Post by: bluesman on February 14, 2011, 04:06:31 PM
Is boiling the starter wort for sterilization or hot break, or neither/both/something else?

I used 10% cause it's easy and in the ballpark.

Sterilization.

Boiling starter wort is necessary to produce a sterile environment for the yeast to grow in.

Hot break will come with the boil but I don't believe it's necessary.
Title: Re: how do you make a yeast starter?
Post by: denny on February 14, 2011, 04:07:14 PM
I assume an uncovered pan, and a rolling boil, with the ten minutes starting at the beginning of the boil? I was surprised by my boil-off results myself, but there it was. I'll test it again for repeatability. As tests go, it's an easy one :) This time, I'll wear a lab coat.

Ooohh, impressive!  A lab coat will definitely guarantee results!  ;)  I do my boil as you describe.  I use a 6 qt. SS post to boil a bit over 2 qt.  I wonder if the geometry has something to do with it?

I wonder if wort boils off more slowly than water.

I wouldn't think so.
Title: Re: how do you make a yeast starter?
Post by: tschmidlin on February 14, 2011, 08:50:42 PM
Give him some chin whiskers and he looks a lot like Tom... ;)
You've got to lose the tie too ;D
Title: Re: how do you make a yeast starter?
Post by: beersk on February 14, 2011, 09:47:05 PM
hmmm I usually do 1/2 cup DME to 1 quart of water.  I think sometimes I use just a little more water to account for boil off.  I don't typically worry about the gravity too much, as I believe 1/2 cup DME per quart of water gets me in the ball park with a 10 minute boil.  Cool the wort, shake, add yeast, shake some more.  I also intermittently shake my starter throughout fermentation also to keep the yeast suspended more. 
Seems to work fine for me.