Yeast Starter - Ratio Question

[Brak23]

I keep seeing a pretty common theme of 1/2 cup of DME to 2 cups of water for a yeast starter. And its a rule of thumb I always followed, and I havent really ever paid attention to much detail beyond that for the starter. My starters have always been ok, but never great.

Well, I upgraded my kit and got a stir plate and a 1L Flask. I did 1 cup of DME to 4 cups of water and ended up right at 1L. I boiled for 15 minutes, cooled and through it in the flask and thats when I noticed that I had a little less than 900mL left, which is 10% boil off. So, knowing that the sweet spot for a yeast starter is 1.035-1.040, I checked the gravity reading and I got 1.055.

So my question becomes, the 1/2 cup DME to 2 cups water, is there corrections that must be made for boil off? I simply topped my starter off with water and got it perfect, but this is the first time I have topped it off with water, so curious if this is common or if I need to adjust my water for boil off.

 

[user 4295]

I have found that it is easier to use the metric system with a 10:1 Water/DME ratio when making starters. For example, if you want to make a 2000 ml starter, just weigh in 200 grams of DME and then add water to bring the total volume to 2000 ml. That should give you the right OG (1.035-1.040) every time. As far as boil off is concerned, I always add a little more water than my desired starter volume to account for the boil off.

 

[flars]

The optimum starter wort is a 10:1 ration of brewing water to DME. A one liter starter wort would have 1000 milliliters of water with 100 grams of DME added to the water.

Weighing your ingredients is more accurate than using volume measures. A good digital scale is about $20 at Walmart. Digital scales are very good to have when dividing bulk hops by the gram.

 

[flars]

Forgot to add this to my previous post. There isn't any need to boil the starter wort for 15 minutes. Pasteurization occurs at about 165°F. Remove the water from the heat when it comes to a boil and stir in the DME.

 

[kh54s10]

The optimum starter wort is a 10:1 ration of brewing water to DME. A one liter starter wort would have 1000 milliliters of water with 100 grams of DME added to the water.

Weighing your ingredients is more accurate than using volume measures. A good digital scale is about $20 at Walmart. Digital scales are very good to have when dividing bulk hops by the gram.

This^^^^^^