[lees_brew]

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

[tygo]

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.

[maxieboy]

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.

[punatic]

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?

[jamminbrew]

I use  1/4cup DME  to 2 qt water, it has worked fine for me.

[denny]

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!

[gmwren]

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.

[maxieboy]

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?

[kgs]

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...

[denny]

Always weigh the DME for a starter.  Volume measurements can give widely different weights.

[maxieboy]

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...

[maxieboy]

Always weigh the DME for a starter.  Volume measurements can give widely different weights.

+1

[denny]

1.100 is obviously too high for starter gravity wort, but tygo's info is correct...

Agreed.

[punatic]

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

[tygo]

Which is a good Specific Gravity for a beer yeast starter

Right, that's what I was saying.