It actually does taste fine (and won’t kill you) when it’s brown. Black, though–avoid. And yes, closing your eyes helps because the brown color affects many people’s subjective experience.
There’s a reason that so many restaurants make guacamole table-side, and it’s not just theatrics.
There are some good tips in this thread for maximizing the life of it, but the key thing is to eat it quickly. It’s a losing battle to get more than a couple of hours out of guacamole, 24 hours tops. Even looking at store brands - by the time you’ve added that many preservatives, I’d just as soon go without guacamole altogether.
In some ways, it’s like the threads on how to reheat a steak. Some methods are better than others, but none of them will make it as good as it was last night.
Funny, I was thinking of the exact same analogy.
Still turns brown that way.
Okay, I’ll try the lemon juice and sealing it without airspace. Maybe water.
I’ll also try making up less at a time.
Can I make half an avacado’s worth, and save half the avocado for later?
Nope. Same problems apply. Just chop up the rest of the avocado onto a salad or something.
Actually, no. It’s green until it moves farther down the line, when it’s mixed with dead red blood cells (one of your body’s waste products). That’s when it turns brown, as anyone who’s ever painted model airplanes would know. 
Don’t sniff the glue!
Then what’s the point? 
This is a little more successful, yes, because there’s much less of the avocado exposed to the air. Lave the pit in the half you’re saving and wrap it with no air spaces. Maybe even brush lemon juice over the exposed part of the avocado.
I would still eat it within 24 hrs if at all possible. If not, you’ll still see the surface turn brown and nasty… but if you cut/scrape the top 1/4" or so off, then the lower parts of the flesh should still be edible.
In my house, though… leftover avocado is an inherent contradiction in terms.
{emphasis mine}
Use only one avocado at time. Then you will eat the whole thing.
Edit: Should have read the whole thread. :smack:
Vermouth, avocado, and steak should all be consumed immediately after opening. Or preparing. Or together. Or something.
Whaaat?!
Shake over ice, strain, and garnish with a twist.
I’ve eaten at, like, a bazillion Mexican restaurants* in the US, and I’ve never seen this done. Are you talking about Latin America?
*And I’m not talking Taco Bell
Guacamole turns brown for the exact same reason cut apples turn brown- enzymatic browning, which needs oxygen to occur.
So there are really two ways to go about keeping your guacamole fresh- prevent oxygen from getting into it or inhibiting the enzyme (polyphenol oxidase), which adding acid (lime juice) does- basically the enzyme works best in a narrow pH range, and adding acid tosses the system out of that range. If you’re using lime or lemon juice in particular, the ascorbic acid also interferes with the enzymatic reaction.
That explains both the water trick and adding lemon or lime juice to guacamole. Personally, I think leaving the pit in doesn’t do squat. It never has for me, anyway, while adding a bunch of lime juice will delay browning fairly effectively.
I wonder if a thin layer of oil might be more effective than water for longer-term storage since the oil won’t evaporate, and after the excess is poured off, the remaining oil film should just mix right into the guacamole when you stir it up.
It’s fairly common around here (Texas), though by no means universal.
My mom uses the pit trick, and it really does seem to work, though I have no idea why or how.
I use lime juice in preparation and press a layer of cling film over the top. I have no idea how long this keeps guac fresh though, because I’ve never had leftover guac last more than a day in my house.
I’m in Oklahoma City and several restaurants do that. Including a couple of chains like On the Border
I saw avocado oil at Homeland, might try that.