Gutter Oil: The History, The Mythology, and the Reality

Online you can find a bunch of videos of people in China scooping oil from the gutter. What are they doing?

Swirling around the internet - from the dark reaches of clickbait farms to the ostensibly lighter corners of elite media - you can find videos of people in China collecting oil from the gutter. The argument then follows that this oil is then frequently used in Chinese restaurants and street food, as evidenced by reports of Chinese authorities busting gutter oil rings.

What we hope we can do is unpack this a little bit, and discuss the facts and fictions of the gutter oil phenomenon. Because you have even a modicum of media literacy, I think a lot of the English-language gutter oil content out there rings a five-alarm bell on our bullshit detectors. But at the same time? The reality is that there’s also a ‘there’ there, too:

Now, I had originally planned to pen a full Substack post on this topic - after all, it’s a topic where the written word would really shine - and you could follow the threads of some of our research. But to be completely honest? Delving into this whole world (especially those darker corners of anti-China clickbait), hasn’t been… fantastic for my personal headspace. We decided to make this video sort of on a whim, when we saw a highly upvoted Reddit post that pissed us off enough that we felt like we had to clear the air a bit. To be frank, I just want to move on to the next video, get back to making delicious food - researching dishes is a lot more rewarding than delving into this swamp. Hats off to journalists that make a living wading through the muck.

So in place of a proper post, here are a few key points from the video that I think should be emphasized. Perhaps one day in the future I’ll swing back to this post and edit it into a proper piece.

Key Takeaways

Videos of people collecting oil from the gutter outside of restaurants is not evidence the restaurant is using gutter oil.

Outside of restaurants in China is a contraption known as a grease interceptor. This is a critical device that helps ensure that oil does not hit the sewage system, generally accessed through a manhole.

The grease interceptor must be cleaned regularly. Specific regulations depend on the city and the district, but the ultimate responsibility is on the restaurant to maintain their grease interceptor. In particular, the fire department takes the situation incredibly seriously.

In many larger cities there is a specific service (that the restaurant needs to pay for, in Shenzhen I recall it was about 5000 RMB per month?) that pumps the grease interceptor with some proper machinery. But the specific situation will depend on the locality. It is not unheard of for a restaurant to clear their interceptor themselves if there is a buildup.

The oil collected in these videos are not being directly used in restaurants.

In many videos - though not all - it is implied that the oil is being collected from the grease interceptor is then being repurposed directly by the restaurant.

Even from the more salacious media outlets, once the story is delved into in detail… it is made clear that the issue at hand is related to subsequent reprocessing of that collected oil. This was, indeed, the crux of the original gutter oil scandal: oil collected from grease interceptors was being neutralized, bleached, deodorized (in a similar way an edible neutral oil is produced) and sold back to restaurants. Due to contamination from bacteria and heavy metals in the sewer system, consuming this oil presents some health risks. But you would likely be oblivious to whether you were consuming it or not in the moment, particular in the context of other flavors.

Perhaps you knew this already, but I felt it was important to emphasize.

Recycled oil also has legitimate uses.

The most common destinations for recycled oils in China are industrial lubricants and biodiesel. It’s worth mentioning that the United States also has a lively market for recycled oil, as it’s a common inclusion in livestock feed (though to be clear, in the United States the oil used in livestock feed is sourced from deep fryers, not grease traps).

In the past, one of the biggest issues was that recycled oil as a cooking oil commanded a 50% price premium over that bound for industrial purposes.

Of course, markets tend to shift faster in the face of price-based carrots than punitive regulatory sticks (though the two can be especially effective in tandem). While the Chinese government has cracked down on gutter oil - as we discussed in the video - perhaps the more important development has been the dramatic increase in demand for recycled restaurant oil for use in biofuels.

Videos of people collecting oil in rather-suspicious-looking unmarked vans (that perhaps respond poorly to being filmed) is not evidence of gutter oil.

Throughout the world, there is the phenomenon of grease theft. While more current information is available from a quick google, this 2000 Salon article province a nice overview.

In the USA, a grease thief will usually need a utility truck to get the job done. In China, it can be as easy as popping open the grease interceptor. This is in large part due to specific multi-compartment designs of grease interceptors that are popular in China (likely given the admittedly rather oily nature of Chinese restaurant cooking).

Recycling restaurant cooking oil is a common practice worldwide.

In the industry, used restaurant grease is divided into brown grease (sourced from interceptors) and yellow grease (sourced from used deep frying oil). The general rule of thumb is that latter has much wider range of potential uses - in the USA, livestock feed appears to be the dominant application - and commands a much higher price.

It is difficult to parse why oil sourced from interceptors in China is recycled while those in the United States is not. The obvious explanation the mind turns to would simply be a lower regulatory bar, which could potentially be problematic. But perhaps the destination of the recycled oil itself requires less of a regulatory hurdle - the dominant (legitimate) uses of recycled cooking oil in China are industrial lubricants and biodiesel. Perhaps some minerals and free fatty acids are less of an issue when you’re not feeding it to chickens.

The standards given to oil recyclers in China would corroborate this idea, as from the document it appears that animal feed is not an allowable destination. But this is an area that we’re quickly bumping into the limits of our understanding, and I’m worried that our analysis could begin to veer into confirmation bias.

The original gutter oil scandal was real and not a fabrication. The most legitimate academic analysis we found put the market share of gutter oil at about 10% during the ‘00s.

It is important to emphasize that the gutter oil scandal was very real, stemming from well researched pieces of investigative journalism and made an indelible impact on Chinese society.

The original gutter oil was called “frying oil” as it was generally being used for deep frying (i.e. an application where low quality oil would have less of an impact on taste). Researchers from Wuhan Polytechnic University estimated that roughly 10% of oil purchased by restaurants during this time was gutter oil, though other researchers had (unspecified) lower estimates.

There was a crackdown in 2011 and 2012 that - anecdotally - dramatically diminished (but likely not extinguished) the market for gutter oil.

I should be quite upfront in that this final point is primarily based off of discussions that we’ve had with friends in the industry. Take as well salted as you would any anecdotal evidence.

Pre-2012, gutter oil was a bit of an open secret, and it was sometimes found in a perhaps surprisingly diverse array of restaurant settings (while you would be more likely to bump into it at a street stall than a hotel, it wasn’t necessarily the case). This has drastically changed post-2012.

However, it is important to note that refined used cooking oil is still something that is available for restaurants to purchase, especially from grey market distributors. Said distributors will make it clear that the oil is not for use as a cooking oil, but it’s certainly possible that there is someone - somewhere - in China that is flying too close to the sun and using this sort of oil in 2024. Everyone emphasized that no restaurant owner in their right mind would use it in the larger cities, but it would probably be wrong to claim it as completely 100% eradicated.