Wyeast 3787 starter help

hello,
In preparation for my fist 5 gallon batch (belgian dark strong ale) I made a yeast starter with wyeast 3787. Mr. malty said to do a 3.6L starter intermittent shaking. I used a 1 gallon glass jug thinking i would have enough head space, but after shaking it once to give it oxygen it overflowed quite a bit. After that i didn't shake it anymore. The starter continued to ferment overflowing with foam for most of the time until it finished. Also the foil came off a couple times leaving the starter open to air for a couple hours, not sure if it might have gotten infected with something. The starter is currently in the fridge, and i was wondering if i should decant and pitch it or have i lost way to many yeast cells when it was overflowing or it might be infected??

Go to the Northern Brewer documentation page for yeast pitching rates. It describes how to make a two step propagation starter. You can basically combine a 2L starter and a 1L starter (after decanting) and make billions of yeast with a small container. I used that method with 3787 and had good success. I also had lots of foam but plenty of head space to let it rise.

http://www.northernbrewer.com/documentation/YeastPitchingRates.pdf

Here it is!

Most likely you did not lose that much, if any yeast so I would not worry about it. In addition, even if the foil came off there was CO2 pushing out so nothing nasty got in. Next time go to http://www.yeastcalc.com and calculate a stepped starter

thanks for the replies