When I go to the supermarket, I never see any bottles labeled “soybean oil”. But if I pick up a bottle of “vegetable oil”, it is guaranteed that the one and only item in the Ingredients list will be soybean oil.
I don’t get it. Why are the soybean oil manufacturers afraid to put the word “soybean” in a large font on the front of the package? Does soybean oil have some sort of stigma which doesn’t apply to corn oil, cottonseed oil, canola oil, or olive oil?
Other than having a bad taste to it?
WAG: to give the manufacturer the freedom to use whatever raw material happens to be cheaper at market. Maybe it’s soybeans right now, but maybe 10 years ago it was corn.
There are a whole range of items that can be used to make “vegetable oils”.
In the UK, it tends to be sunflower or rapeseed (= Canola?).
Interesting, ‘vegetable oil’ here in the UK is most likely to be rapeseed oil. Soya oil would probably be labelled as such and would be a niche item (we can’t really grow soybeans in our climate very well).
So I’d be inclined to say that ‘vegetable oil’ might be a nicer-sounding euphemism for ‘the cheapest oil we can put in a bottle’. I suppose it also means suppliers can change the ingredients (so as to keep up with whatever is cheapest right now) without having to declare it as a new or different product.
Some of the supermarkets did a similar thing here with their cheap own-brand cheese for a while - it always used to be ‘mild white cheddar’, but they changed the packaging to ‘mild cheese’ so that they could substitute other kinds of cheese if they were cheaper and available, without needing to print new packaging.
It is also possible that it is a blend and the ‘vegetable oil’ gives them freedom to put in whatever they have to hand.
This is pretty much my guess, but there are a few problems with it:
We’re not talking about a product that is as fickle as the stock market. Vegetable oil has been soybean for at least ten years or more. Please tell me about the UK: Has it been consistently rapeseed, or do they occasionally put a different oil in those bottles?
Similarly, my recollection is that soybean oil wasn’t common in the US until the 1980s or so. Does anyone remember what the popular oil was before that, and whether it was labeled as “vegetable”?
When I was growing up (70s-80s), IIRC, “vegetable oil” was usually corn oil.
I expect rapeseed oil to become less often used in generic vegetable oil as it is becoming a ‘niche’ item itself - I have seen many celebrity chefs espousing the qualities of rapeseed oil as a healthier (and British) alternative to olive oil:
Pretty consistently - although a fair bit of it is probably imported anyway - some ‘vegetable oils’ contain other things too - I’m not sure that the labelling regulations here would permit a generic ingredients panel, but it’s probably still easier to get your revised product on the supermarket shelves if you don’t have to present it to the buyers as a new item.
But I suspect it’s largely an image exercise to try to move away from the local public notion of ‘cheap and nasty’ rapeseed oil fits that category here; soybean oil fits it where you are - both are sold as ‘vegetable oil’ - I think that is the basis of a fairly compelling argument that the manufacturers don’t want us thinking too hard about the product’s humble nature.
Back to the topic:
I agree that it is called vegetable oil in order to be able to include whatever veg is cheapest for making oil at the time, probably in combination with other oils.
What always cracks me up is the inexpensive “vegetable oil” (contents: soybean oil) for $4.99 a gallon on the bottom shelves, and a 6 ounce glass bottle of “soy oil” on the top shelf for $14.99.
People are stoopid.
(And soybean oil is a great bug repellent.)
I always thought “cheddar” was what they called cheese if it wasn’t interesting enough to be any other sort of cheese.
(Proper vintage cheddar, of course, is a whole different issue.)
(This will probably sound sarcastic, but I really really do not mean it that way!)
As I posted already, I – here in the USA – have never seen anything in the ingredient list of “Vegetable Oil” anything other than “soybean oil”. I see that you are in London, and it coudl be that things are different there. Please check a few bottles of your vegetable oil, and let me know if it contains anything other than rapeseed oil.
Or could it be that in the UK the “vegetable” word suffices, and the label is not required to specify exactly which oil(s) it is made of?
Another WAG-- labeling a product “vegetable oil” assures wary cooks whose recipes simply call for “vegetable oil,” when they might be afraid to substitute perfectly-acceptable canola/soy/blend oils.
I’ll second this. “Vegetable oil” used to be corn oil. Then Corn Oil became it’s own category when soybean oil took over (IIRC, about the same time Canola Oil started getting a lot of hype). I’d agree that “vegetable oil” is probably whatever’s cheapest - it’s just that soybean oil has been cheapest for a while.
In the USA all the different types of oil mostly started being sold as a type, when different cholesterols were stressed as good for the heart or bad. These differentiations became common in the 1980’s Corn oil was the most common vegetable oil here before soybean.
Canola oil is almost always labeled as canola oil around here, but then this is the heart of canola production. In fact it was developed not 10 miles from where I’m sitting.
According to the information at the ConAgra website page devoted to Wesson, there was a “vegetable oil” division of the Southern Oil Co. back in the 1920s. Wesson Oil, itself, started as cottonseed oil. Presumably, then, “vegetable oil” is a generic, longstanding term for whatever basic vegetable-based oil is being marketed. That it currently happens to be soybean based has more to do with two things: there are a LOT of soybeans grown these days (part of a healthy farmland crop rotation management program), and, as you suspect, they don’t have enough caché to merit a category of their own. Pity the poor soybean. 
ETA: Wikipedia notes that soybean oil basically replaced cottonseed oil as the vegetable oil of choice by the '60s.
This.
Or, distill it further.
“Vegetable Oil” sells better than “Soybean Oil”.
My guess, anyhow. Oh capitalism! What can’t you explain?