ISO advice on mayo or butter, mixed with other things

[kohnuma]

I'm back

The OP is new to this site and did not know she would not get email messages alerting her to responses. I meant store-bought mayo, as homemade usually does not come with an expiration date. Thanks for all the info and weighing-in; it seems safest to take a majority view and use mayo concoctions within a couple of days, freeze the ones made of butter in an airtight non-plastic container, and mix non-H20-based ingredients where viable. BTW I keep mayo around forever too, though I don't know how long forever is in our house, maybe six months? And I'm still alive.

 

[BreezyCooking]

When I use mayo to make something like aioli, or tarragon mayo, or tartar sauce, I keep any leftovers for 2-3 days tops, then toss. However, I'm also one who keeps opened jars of mayo in the fridge until they're used up - definitely longer than 2 months.

As far as flavored or "compound" butters, they are TERRIFIC kept in the freezer for many months. I can't give you an exact shelf life because I always use mine up fairly soon (as I try to do everything in my freezer on a regular basis). But making compound butters, rolling them into logs, wrapping well, & freezing is a longtime safe method of having them on hand to slice onto grilled meats & fish. And the quality does NOT suffer.