I never leave butter out at room temp unless I'm going to use it that day. DH hates soft butter. His mother would leave out a bowl of it and boy did it smell bad.
I have never left homemade out long at all. The store bought i leave out covered for a couple days max. Homemade never lasts more then a day around here! LOL
For safety, especially if unpasterized milk was used, no more then a day. Again, JMO
I've got a Butter Bell that I use for counter butter... so far, after over a year, it's held up to the manf. claims*... but that's using store bought butter (one stick fits perfectly) or homemade from store bought cream... donno if you used farm fresh cream?
NO one, even the kitchen stores, around here carried one so I had to go online... of the reviews I found LT looked the best... the all glass ones slide evidently, so while I coulda ordered one from Wally World it didn't seem worth it to have my butter slide into water.
You can snoop at the brand I bought at http://www.butterbell.com/
Or, you can go to http://myworld.ebay.com/originalbutterbell and see what's happening there.
I ordered a case of the Pasta Plates (LOVE Them) and a BB too, well, you can read the feedback.
Jesse George gives great customer support which I love.
Gee, think I like my bell or what? Actually, it's pretty well any kitchen gadget. *blush*
And NO, I don't sell the things, but if I had a shop I definitely would because I know the things work.. can't say the same for other items. *cough* CPU fan *cough*
back when we had Jerseys we kept our butter in a butter bell in the central Ca heat. It got used quickly but we never had a problem. I think a lot would depend oh how completely you washed out the buttermilk.