What happened my yeast starter?

[Shanna]

Hi there

Was hoping somebody could comment and let me know what has happened my yeast starter.
I made up a batch of 50gr of DME IN 500mls of water. I pitched a jar of yeast slurry and I put it in the kitchen. I left it for two days and the yeast appeared to start to work. I got a whiff of fruit and the start of a krausen.  I then added another 500ml with another 50gr of DME and then everything stopped. I thought it mighft rom fromt the kitchen was too cold so I left it close to the radiator but no luck. I get an acrid smell from the starter now that makes me think that maybe I burned the DME in the 2nd lot.

Shanna

[Ciderhead]

When scaling up I pour off as much of the first fermented wort as I can without losing any yeast and put fresh wort in on top.
I like to do more jumps
So 50; 250; 1l 3l

[Tom]

Could have shocked the yeast with sudden change in temperature from one 500 ml to the next?
Burning the sugar shouldn't affect the yeast health, really.