[pmallory]

I canned my first batch of starters using a pressure cooker. I followed the usual recipe for starters, 1 cup of light DME per quart of water. I feel the color of the starter, after the pressure cooking is much darker than it should be, or than it was before I cooked it. Is this some sort of Mailard reaction? Or could this color change be in my head? Anybody else notice something similar when they do it?

[Matt B]

I go with 1lb DME per gallon of water for a gravity of around 1.050, not sure what a cup ends up being, the only times I've noticed the wort being darker was when I used amber instead of light DME. If the DME is old, it's oxidized a bit (totally fine for a starter) which will tend to darken it a bit. If you had the flame on super high and was doing a *really* vigorous boil for at least an hour (I only go 15 minutes to sanitize) then possibly some maillard reactions. Other than that, either too much DME for the volume of water, serious boil off, I can't think of any way the wort could end up being darker.

Even then, I wouldn't worry about it. I usually chill the starter to put the yeasties to sleep, and decant off the excess liquid. Even if you're doing a pils or something, i can't imagine the residual color from the yeast contributing that much to the final beer.

[Hokerer]

Can't help you much as I use the "extra" wort from each batch as the source of my starters (no DME).  Because of that, the color of my canned starter wort is all over the map depending on what kind of brew it came from.  But, like Matt said, if you chill and decant before pitching, you don't need to worry what color that wort may have been.

[tschmidlin]

Yes, it is Maillard reactions.  I see this a lot in labs that that autoclave their media with the sugar in it.  My lab autoclaves the base media and sterile filters a 50% glucose solution, then you add glucose solution to the base to get whatever level of sugar you want.  It is mostly a cosmetic effect and nothing worth worrying about.

[dshepard]

I have made a number of 5 gallon batches of starter wort with both DME and a simple AG mash. Both of them darken up a bit after pressure cooking. BTW, the extra time involved doing an AG mash more than offsets the cost of the DME, at least for me. 

[tubercle]

I can wort all the time.

I first boil it to get rid of the hot break so it doesn't do it in the jars.

Usually the pressure cooker is used for 30 minutes for quarts but I have also done a 120 minute hot water bath will no ill effects.

 Edited to remove potentially fatal statistical reference.

[morticaixavier]

I can wort all the time.

I first boil it to get rid of the hot break so it doesn't do it in the jars.

Usually the pressure cooker is used for 30 minutes for quarts but I have also done a 120 minute hot water bath will no ill effects.

99.9% of the time you will have no ill effects by not using a pressure canner but the other .1% with botulism is a real bummer! and unless you live fairly far below sea level you are not getting hot enough to destroy the toxin.

[tubercle]

I can wort all the time.

I first boil it to get rid of the hot break so it doesn't do it in the jars.

Usually the pressure cooker is used for 30 minutes for quarts but I have also done a 120 minute hot water bath will no ill effects.

99.9% of the time you will have no ill effects by not using a pressure canner but the other .1% with botulism is a real bummer! and unless you live fairly far below sea level you are not getting hot enough to destroy the toxin.

 I agree, no use in becoming a statistic. I used to hot water bath tomatoes but everything now is exclusively pressure canned. If you got the tools you might as well use them.