How long can fresh grapes sit?

[KTWineMaker]

I'm purchasing some Syrah grapes from the Western Slope of Colorado. They are being harvested this week and ready for pick up starting tomorrow (Friday). How long can they sit for without being crushed? It's quite a far drive so I'm struggling to find a date before Tuesday that I could go grab them. I'm not what issues I'll run into if they sit too long.

 

[NorCal]

What will the ambient temperature be? Four days in hot weather will not be good for the fruit.

As a reference, the local winemakers I sell grapes (55 tons / year) to want their grapes within hours of picking. We have only had grapes sit over night once and that is when their truck broke down. Our conditions may be extreme with 100 degree days in the summer, which would put a lot of pressure on spoilage. The fruit we sell to the east coast gets shipped locally within hours and is put in very cold storage. It is then shipped in refrigerated containers to the final destination.

 

[KTWineMaker]

The temperature in the area is in the 100s so probably pretty similar. He said most of the home winemakers were coming up the following day. I'll ask him what kind of storage conditions he has (its a horticulture research center).

 

[grapesforwine]

We typically harvest starting around 2-3 am, and then starting around 7-8 am the grapes are hauled off for processing.

We do not recommend letting grapes sit around at room temperature indoors, and especially not sitting around outside in direct sunlight for more than 4 hours.

If you have the ability to store them refrigerated or temperature-controlled at 55 or lower, you might be able to get away with it for up to 3-4 days.