Start a starter when

How long before you brew should you start a starter? I think I'm going to brew on Friday.

I'm brewing tomorrow...well later today (Thursday) actually according to my computer clock...and I made my starter Tuesday. Shoot for the starter to be active about 2 days or so before you brew, most people who dump the whole starter in pitch when its at high krausen.

My starter was a burp every about 6 seconds when I pitched it, which took roughly 24 hours. It worked great as fermentation started in the primary in about 4 to 5 hours. Real glad you guys convinced me to make one

I've pitched at both ends of the extremes. I pitched my Arrogant Bastard clone at about 18 hours and my nut brown at three days and both turned out great. I've been told (several times) that one of the primary functions of a starter is to confirm your yeast is healthy, if you have krausen it is ok to pitch. Just like everything else in brewing (or so it seems to me) it's all a matter of personal preference. I've read that some people like to pitch at full krausen (18-24 hours) and some like to pitch after everything has settled down (24-48 hours).

I always look at it as insuring I have heathy/viable yeast. It's like having a GREEN light to brew.

i pitch mine at 18-24 hours after making it. while it's still active....