I just don’t get it. I’m sure there’s a very sciency explanation, but it makes no sense to me. I love that it can sit out to be soft and spreadable, but you try that with cream and you’re on the way to a stinky cheese, milk or yogurt you’ve just got a curdled surprise.
So why can butter just sit out and not start to stink or become dangerous to eat?
In: 122
I feel there is a true ELIF missing.
Here’s my try. Food doesn’t go bad by itself. If you threw a hot dog into space it would be fine to eat for a very very long time. What happens is little creatures, like bacteria and fungi start eating some components of the food. Most of them need also water and oxygen to live, but some don’t. Also, some parts of the food can go bad from contact with oxygen (oxidation) sunlight (UV) or degrade with changes in temperature. Butter is made by removing most of the water, and the remainder is in very small separated droplets so microorganisms can’t damage it easily.
However oxygen and light do degrade the fats in the butter, creating a rancid flavor. So even if its safe to eat, the taste will grow worse after a few days without refrigeration.
The “sciency explanation” is just “bacteria need water to live and grow in”.
Milk/cream/yogurt contain lots of water, so the spoily bacteria can live in them. Butter is almost entirely fats/oils and much less water, so bacteria can’t live on it.
A quarter pound stick will only have about 24 hours or so to decompose until it is consumed where I’m at, so that problem never arises this time of year. There are some spring, and summer, and fall days that will turn a stick of left out butter into a yellow pool of goop though.
I have had butter go bad when left on the counter during a hot summer. I have even seen refrigerated butter go rancid (it was at my SILs house) my partner and I said no thank you to buttering our toasts.
Butter *can* turn rancid though….made the mistake of leaving it out during a very hot week with no A/C.
Butter actually does become rancid, it just takes much longer because it’s mainly fat and bacteria doesn’t grow as well in fat as it does in water. Milk etc. has more water than butter does.
If you put a stick of salted butter and a stick of unsalted butter out on the counter for a month, and try them afterward, the unsalted butter will have gone rancid. The salted butter will still be fine to eat. (Ugh. Ask me how I know.)
I say it’s the salt. Not only does it improve the butter’s flavor, it also acts as a preservative.
Butter goes rancid if left out in the warm, but it only affects the taste afaik. I don’t think it’s dangerous to eat?
> water molecules in butter become separated by fat, which is almost impenetrable to bacteria. This protects butter from microbial growth. Salted butter is even better protected because the salt contributes to its stability. For this reason, butter can be stored safely on the counter.”
Fun fact:
There is a ‘lip’ on a butter dish, on the base between the butter and the outer edge. It’s there because long ago folks used to pour a bit of water into this little area so that the lid sat in it, which kept air from getting to the butter and kept it fresh longer.
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