Time frame between collection of wort and boil

[boomtown25]

I am in the middle of my mash today and have a feeling that I am going to be summonsed to something I can't miss and will get my brew day interrupted. Is there any concern if I collect my wort properly, put lid on boil pot and save boil for tomorrow???

 

[Lefou]

Delaying a boil can risk a possible infection.
If you have space, you can refrigerate unhopped raw wort in a covered or sealed container and boil later if you're careful. I typically lauter, collect wort, and boil immediately. Boiled wort with hops can last longer than raw wort because it is sanitized by heat, reducing possible vectors for spoilage.
I've done some unconventional things with my beer ... like covering the boil kettle with cellophane wrap and poking a vent hole or two in it, then putting the lid on it as it cools in a slushy snowbank for a couple hours. At the time I was shoveling a driveway and took advantage of the February storm to get a brew day in. The kettle was a 5gallon pot with no valves so no contamination could get in unless the lid was upset.
Beer turned out great, I'm drinking that batch now ...

 

[yourlastchance89]

I have had brewdays where in anticipation of an event, I have completed the mash and let the wort sit covered for some hours before boiling with no ill effect. Typically when done mashing I'll raise the temperature to just under boiling, cover the kettle with the lid, and resume later. While Lefou may be correct in stating there may be an increased risk of possible infection, I believe that risk to be very minimal, especially considering you will be boiling it later, and if you raise the temp of the wort to 200°F - 212°F and keep the kettle covered with a lid.

 

[Lefou]

Unhopped wort will easily last several days or a week if handled properly.
I've saved second runnings as "grain tea" and it's lasted for days in refrigerated second-hand sanitized milk jugs here at home.