Second runnings starter info

Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum

Help Support Homebrew Talk:

RotorHead6

Well-Known Member
Joined
Jan 16, 2007
Messages
86
Reaction score
0
During my brew day yesterday I took two gallons of second runnings and saved to make starters with. I did this to save money on using DME all the time. I had a gravity reading of 1.020. I would like my gravity to be at 1.040 for starters. I froze the wort in .5 gallon batches.

My question is when it comes time for a starter, how much DME would I add to obtain a gravity of 1.040? I also thought about boil off to obtain a 1 quart starter but I also can't figure out what the gravity would increase to if I boiled off half of the liquid. Thanks for the help.
 

Piotr

Well-Known Member
Joined
Jun 18, 2008
Messages
463
Reaction score
6
Location
Poland, EU
Just go ahead and use 1.020 wort, yeasties will by even happier with thinner wort.
 

SpanishCastleAle

Well-Known Member
Joined
Jan 5, 2009
Messages
4,339
Reaction score
45
Location
Central Florida
but I also can't figure out what the gravity would increase to if I boiled off half of the liquid. Thanks for the help.
Figuring points is easy. Just remove the '1' from the gravity reading and use the digits to the right of the decimal as 'points'.

So 1.020 is 20 gravity points. If you are boiling it down or adding water to dilute it just divide or multiply the points by the ratio of the before/after volumes. So if you had 2 gallons of 1.020 wort and boiled it down to 1 gallon you'd have: 20 * 2/1 = 40 points. Your new gravity would be 1.040. If you aren't sure whether to multiply or divide by the ratio (or you get the ratio 'upside down') then just use a little common sense: Boiling it down will increase the gravity so your answer should show an increase in gravity. So in the example here...multiplying by 2 and then dividing by 1 will increase the gravity number. If you had mistakenly multiplied by 1 and divided by 2 then your answer would show a decrease in gravity which wouldn't make sense. It's really that simple.:)
 

Ender

Well-Known Member
Joined
Feb 27, 2007
Messages
245
Reaction score
2
Location
Columbus, Oh.
I agree, just use the 1.020 wort. It's a little low, but the yeast wont mind. To figure out the gravity numbers use this from Ray Daniels book:
Begining gravity * begining volume = Ending gravity * ending volume

so in your example:
20*2=X*40
so X=40/40 or 1 gallon

you can use this formula for anything any time. use it at the begining of your boil to find out what your ending gravity will be for a specific volume. Or use it for a known ending volume and ending gravity and find out how much beging wort you need or what the gravity should be.
 
Top