So
if you’ve ever
heard of rapeseed oil, what you’re probably
talking about is an oil made from the Brassica
Napus plant, commonly called oilseed rape.
It itself was a mix between the cabbage brassicas
and the turnip brassicas and likely hit the
scene about five hundred years ago in Europe.
People in Europe weren’t really too into
the taste though, so it while it did pop up
for cooking in places, it was mostly used
for fuel and lubricant.
All well and good, until researchers in the
early sixties discovered that one of the compounds
in rapeseed, and mustard seed oil for that
matter, erucic acid, could potentially damage
the heart.
Now I am very much not a toxologist so I’ll
try my best not to editorialize this part
too hard here… but apparently after feeding
rats up to 70% of their daily calories in
the form of high erucic acid oil … those
rats developed some short term heart problems.
Some follow up studies confirmed the effect
in piglets, and so, of course… rapeseed
oil was banned for human consumption in the
United States and many other Western countries,
despite basically all later studies finding
zero link between erucic acid and heart disease.
That said, I’ve left some proper sources
for you in the description box, because you
definitely shouldn’t automatically trust
the word of some random dude on the internet.
To a rescue came a pair of researchers from
the University of Manitoba who developed an
oilseed with far less erucic acid by crossing
it with Brassica Rapa, or Turnip Rape.
They proudly called their new oil Canola,
Canadian Low Acid Oil.
The new plant was cheap and easy to grow in
North America, so industrial producers could
take the seeds, process the living crap out
of them into a tasteless neutral oil… and
that is what’s on your grocery store shelf
today.
Let’s back up a bit, tell the Chinese side
of the rapeseed story.
The first recorded use of caiziyou dates back
to the Qimin Yaoshu at the time of the Northern
Wei, when it was a common cooking oil together
with Perilla, Hemp, Almond, and Sesame.
This plant, however, was called Man Qing…
which corresponds to modern field mustard,
Brassica rapa subsp.
Oleifera.
Now fast forward to late 19th century, when
European traders introduced their Brassica
Napus oilseed rape to China.
In order to get the plant to grow better in
the local environment, farmers crossed the
imported oilseed with the local field mustard
to get this: a cultivar that’s known in
English as semi-winter rape.
But check out the cool symmetry here.
Both canola and Chinese semi-winter rape are
crosses between Brassica Napus and Rapa.
And just like canola… by happy accident,
this cultivar is also significantly lower
in erucic acid than oilseed rape.
Not quite as low as the Canola varieties,
but y’know… comparatively close.
Now enter… capitalism.
See, if you want to be a player in the global
rapeseed game, you gotta play by the global
rapeseed rules so graciously bequeathed to
us all by the culinary cardinals at the FDA.
Which’s generally a maximum of 2% erucic
acid.
10%?
Not good enough, past few decades of research
be damned.
So around the time of China’s entrance into
the WTO, the Chinese government explicitly
wanted to get farmers to use low acid strains,
either the Canadian varieties or hybrids…
so these days about two thirds of Chinese
rapeseed is low acid.
Industrial oil producers then use a blend
of these two seeds to get their oil on the
right side of the bar.
So is caiziyou “rapeseed oil”?
I mean… in some ways it’s weirdly a lot
closer to Canola.
But if you imagine canola oil in your head,
you’re probably imagining a bland, flavorless
oil.
But Caiziyou?
Is definitely not that.
The real difference is in the production.
So step one to a Chinese caiziyou production
is toasting.
Traditionally this would be done in a wok,
but nowadays one of these machines are usually
used, and roasted until the seeds hit about
120 centigrade.
Especially when using the Chinese semi-winter
rapeseed, this roasting process helps volatize
some of the sulfur compounds that can sometimes
give rapeseed oil a bit of an off taste.
The oil’s then extracted using an expeller
press, obtaining this sort of oily sludge
as an end result.
Then that’s tossed in a centrifuge to separate
out the oil, then filtered again to remove
any solids remaining… and that is how you
get caiziyou.
Now these days you can actually still find
some people making traditional European rapeseed
oil, particularly in the UK and Ireland.
These oils are cold pressed then filtered,
kind of akin to extra virgin olive oil.
See, expeller pressing heats up the oil in
the process, which removes impurities but
also flavor.
Keeping the whole process under 122 centigrade
retains both… so you do get a bit more of
that rapeseed nuttiness, but at the cost of
a very low smoke point.
Which is… unfortunately… kind of a no-go
for Chinese cooking.
Making Canola oil, meanwhile, is more or less
an industrial process.
The seeds are first steamed, and the oil’s
then extracted using a hexane solvent, which
is more efficient than either cold or expeller
pressing.
At that point, it’s then refined, bleached,
and deodorized.
First up is refining, or neutralization, which’s
accomplished by washing it with a strong alkaline
such as sodium hydroxide which bonds with
the free fatty acids in the oil to form soap
– which’s then removed and leaves the
oil with its characteristic neutral flavor.
After that, the oil’s bleached which sounds
scary but really just means passing it through
a clay material meant to naturally bleach
like fuller’s earth or activated charcoal.
At that point, it’s deodorized by heating
the oil up to around smoke point and passing
steam through it to remove any last vestiges
of flavor.
And that is… canola oil.
So no.
While it’d be nice, unfortunately Western
supermarket canola oil is far from a direct
caiziyou substitute.
So.
For homecooks outside of China, you’re left
with three choices depends on your level of
obsessiveness.
For the Sichuan food diehards, if you’re
in the US at least it’s difficult but still
possible to find Caiziyou.
We’ve heard reports that big jugs are at
least sometimes available at the Great Wall
supermarket chain, so if you live in one of
these cities, that’s something to check
out.
Also, as of about a week ago, the online retailer
Mala Market started legally importing caiziyou
and selling it on their website.
It’s the first time I know of that it’s
actually available online, which’s really
potentially a gamechanger.
Full disclosure that we do cooperate with
Mala market - they give discounts to our Patrons
– but trust me that even if we had zero
connection with them I’d still be yelling
this good news from the rooftops.
Seriously, check them out… they also sell
Sichuan erjingtiao chilis on there, which’s
another fundamental but hard to find Sichuan
ingredient.
Now if you want to dial the obsessiveness
back a bit, there is one potential substitute
for Caiziyou that we’ve found hits most
of the same notes: Indian mustard seed oil.
It’s got the same sort of pungency and nuttiness
as caiziyou, but it does have that distinctive
mustard-y nose hit.
Luckily that mellows out a lot after cooking,
so… definitely an option.
Unluckily though, mustard seed oil has to
deal with an even bigger erucic acid headache
than caiziyou, because mustard seed doesn’t
really have any low acid varieties.
Fortunately, they do seem to successfully
skirt around the issue because - the stuff
also has traditional religious usages in Northern
India.
So you can buy mustard seed oil, but the FDA
makes them carry the label “for external
use only”.
Because of course, you know, you’re totally
just going to buy this stuff for traditional
Bengali massage…
But suppose you want to dial the obsessiveness
back even further.
Let’s say you don’t really care much about
mimicking the exact flavors of Chengdu and
you just want to, I dunno, make a tasty Mapo
Tofu.
In that case, just do what many Chinese restaurants
outside of China seem to do and… just use
Peanut oil.
It’s got a great balance between flavor
and smoke point, it’s a perfect all purpose
oil… just know that there’s a little that’s
being lost in the translation.
So many Chinese recipes call for cooked Caiziyou
because it has a more earthy taste and then
less of a pungent obvious taste than raw Caiziyou.
In stir-fries you don’t really have to use
cooked caiziyou because the oil will heat
up anyway… but for something like chili
oil you do want to cook your caiziyou.
So what you do is that you heat the oil up
to ~220 degrees centigrade, where it’s like
a lot of smoke coming out, let it go on for
about a minute… and then shut the heat down.
And then let the oil come down to the temperature
you want it to be.
Uh, so right.
I know we’ve been a little bit slow in uploading
videos recently… but, you know, special
period.
But!
You can go to Instagram and check out some
of the food that we cooked up during this
lockdown period.
As always, a big thank you for everyone that’s
supporting us on Patreon… and of course,
subscribe for more Chinese cooking videos.
