On opening a new jar, I usually scrape it out of the jar into a mixing bowl, give my arm a workout stirring it, then put it back in the jar. Bonus, I get to eat the residue left in the mixing bowl.
Also, I try to buy peanut butter from stores that sell a lot of it, so the jar hasn’t sat on the shelf too long - it’s well mixed at the factory, and the less time passes between shipping from the factory to my buying it, the less dry thick paste there is congealed at the bottom of the jar.
It doesn’t even connect to the Internet. Worthless.
I usually flip the jar upside down a few days to a week before i know i’ll need to open it, sometimes i’ll even give it a really good shake before i open it and stir it through.
Keep an eye out on the next kickstarter, The Buttero.
Does not work well with jars where the freshness seal inside the lid is wax paper instead of metal foil. Also, a jar of peanut butter never stays unopened that long around here.
The Costco/Kirkland organic peanut butter, the label of which resembles Laura Scudder’s, stays astoundingly consistent through the whole jar. Like Scudder’s, only two ingredients: peanuts and sea salt.
We don’t have many single-purpose gadgets, but this one is a true friend to the peanut butter consumer.
I wonder, do many stores have a grind-your-own-fresh-peanut-butter machine, or am I just lucky that my local co-op grocery store has one?
They keep it stocked with organic peanuts, and have a supply of new/empty plastic deli containers there (which are a bit wider at the top, and so it’s easy to get all the peanut butter out of them) or you can bring your own jar. I guess you have to like crunchy, and salt-free (though you could mix your own salt in at home, I guess, but I never do). It’s so fresh and delicious, and perfectly blended because you’ve just ground it fresh, there’s no comparison to any peanut butter that comes in a jar.
Scudder’s is my jam. Or rather my PB. I seriously love it, i have had some other organic ones with no added ingredients that were just as tasty but when i can i try to buy Scudder’s.
A couple of stores near me have these. HEB, Central Market and a couple more. I believe they have various “flavored” ones like light roasted, salted, etc. I haven’t gone out of my way to try them but i have been curious to check it out.
Other posts here have mentioned the upside-down storage trick. My experience is that you have to get the timing right, or you still wind up with rock-hard precipitate and clear oily supernatant, just in the opposite order.
What we need is a device. It would rotate the jar very slowly, about two or three turns per day, around a horizontal axis, so that the mixed peanut butter would be in constant motion at, approximately, its maximum flow rate.
It would make a great companion to the device described here. (Indeed, without it, or its equivalent in manual labor, this device has no prayer of moving the peanut concrete that currently sits in my cupboard.)
I don’t particularly mind if the part of the jar closest to the lid ends up with less oil as that’s the part that’s easiest for me to mix up, but yes ideally you’d want to time it just right to minimize how much mixing you need to do. I have found that shaking the jar before opening helps a little bit as well.
My hero.
You monster.
They have a fix for that, too:
I recall that device, my problem is that i’d be far too lazy to clean it up. A knife is pretty low effort to deal with, especially if i’m already using it to make a sammich to begin with.
so, the cool thing about it is the top acts like a squeegee - when you pull it out, it’s basically clean. And the top becomes the lid of the jar. 
it’s cheap, and I bought it thinking “meh, maybe?” But it ended up being a lot easier than just swirling around my knife in there, especially when the bottle is near-full.
My idea would be something along the lines of a fat toothpaste tube. The concept works pretty well for even my thickest oil paints.
There are squeeze bottles of PB and one would assume they controlled the formulation of the peanut butter so it would work without stirring.
But I agree that getting your own freshly ground PB at the store is by far the best. It stays creamy for a while, and you can just buy a few ounces at a time. It is easier just to get more the next time at the grocery store than to stir, or clean that monster.
Reckon there’d be a fair amount of money to be made licensing this to the Nutella people.
Astronauts have been using that technique since the 1960’s. However it’s not always mess-free, as Don Knotts discovered in the 1967 film The Reluctant Astronaut:
But, can it dance?
