Question on canned starter wort

I'm going to can some wort for starters in my pressure cooker.

If I make a starter and need to use 200 ml wort from one of the jars, do I need to dispose of the rest of the jar once it's been opened, or can I close and refrigerate it for use when I step up. Would I need to boil it at that point?

Not sure how quickly or easily it becomes contaminated after opening.

 

My practice is to dispose of any unused wort. You spend so much time and effort making the wort sterile, that I would hate to open it to infection while in the fridge and after being opened. Plus there's a lot of break material in the last 100-200 ml that I throw away anyways.

 

I'll second this.

If you need to do smaller starters, just use different size canning jars (1 pint, 1 quart, 2 quarts, etc) and you'll have flexibility. That's what I do. 1-qt or 2-qt.

MC