Unravelling the mystery that is asparagus

Asparagus “…transforms my chamber-pot into a flask of perfume.”

– Marcel Proust (1871–1922)

I was a strange kid growing up so it’s probably not that hard to believe that I liked vegetables. What is perhaps the most difficult to comprehend was that I liked asparagus. Actually, I loved it! Was it the flavour? The texture? The amusement I got from my acrid smelling pee? Most likely a combination of the three.

Fast-forward three decades to the beginning of 2015; I’m 35 years old, married, and we’re moving to Germany from April to July for my wife’s work. “Awesome,” I thought. “Beer and chocolate for every meal.” Imagine my delight when I found out that it was also spargelsaison (asparagus season) during that time. Here is the background of what I was getting into:

Asparagus is very popular in the Netherlands, Spain, France, Poland, Belgium, Germany, Austria, Italy and Switzerland, and is almost exclusively white; if not, it is specified by the local language term for “green asparagus”. White asparagus is the result of applying a blanching technique while the asparagus shoots are growing. Compared to green asparagus, the locally cultivated so-called “white gold” or “edible ivory” asparagus, also referred to as “the royal vegetable”, is less bitter and much more tender. Freshness is very important, and the lower ends of white asparagus must be peeled before cooking or raw consumption.
To cultivate white asparagus, the shoots are covered with soil as they grow, i.e. earthed up; without exposure to sunlight no photosynthesis starts, so the shoots remain white in colour.
Only seasonally on the menu, asparagus dishes are advertised outside many restaurants, usually from late April to June. For the French style, asparagus is often boiled or steamed and served with hollandaise sauce, melted butter or olive oil, Parmesan cheese or mayonnaise. Tall, narrow asparagus cooking pots allow the shoots to be steamed gently, their tips staying out of the water.
During the German Spargelsaison or Spargelzeit (“asparagus season” or “asparagus time”), the asparagus season that traditionally finishes on 24 June, roadside stands and open-air markets sell about half of the country’s white asparagus consumption.

I was a little confused when we first arrived in Bonn and I made my way down to the town square. Vendors in vegetable stalls were yelling over the top of each other in the same way that butchers do in a typical wet-market, however, on this occasion they were selling white asparagus. White asparagus? “White Ivory?!?” Could that be the asparagus equivalent of the white rhinoceros? It sure sounded exotic, but I wasn’t sure if it was some dodgy black market thing that I shouldn’t be eating.

Over the course of our time here I’ve found that everybody in the general region embraces asparagus, especially at this time of year. A lot of restaurants have degustation menus of a variety of asparagus dishes, like this one we saw in Utrecht, Netherlands (right). Others just do their regular dishes, but add asparagus to a lot of the them or add five or six asparagus specials to the overall menu.

This can make for an amusing time after the meal, especially if it turns into a night of drinking. It’s probably a different situation for women, but depending on the disposition of the man, using a urinal not long after eating asparagus can be an embarrassing situation. The odour. Oh, the fragrant aroma of asparagus piss. Some just shrink back into their clothes like a scared turtle and hope the others won’t notice. Other fellow urinal patrons will just smirk, nod, make direct eye contact, and ask, “Spargel (asparagus)?” A sheepish “Yup…” is the general reply.

I know what some of you are thinking, “Asparagus doesn’t make my pee stink.” Well, let me pop that little bubble of delusion for you right now. Asparagus makes everybody’s urine smell, generally within 15-30 minutes of consumption, it is just that not everybody possesses the enzyme that can detect the odour. Again, from Wikipedia, but you can check the journal articles if you feel so inclined:

There is debate about whether all—or only some—people produce the smell, and whether all (or only some) people identify the smell. It was originally thought this was because some of the population digested asparagus differently from others, so some people excreted odorous urine after eating asparagus, and others did not. In the 1980s three studies from France, China and Israel published results showing that producing odorous urine from asparagus was a common human characteristic. The Israeli study found that from their 307 subjects all of those who could smell ‘asparagus urine’ could detect it in the urine of anyone who had eaten asparagus, even if the person who produced it could not detect it. However, a 2010 study found variations in both production of odorous urine and the ability to detect the odour, but that these were not tightly related. It is believed most people produce the odorous compounds after eating asparagus, but only about 22% of the population have the autosomal genes required to smell them.

This banner is near our house. Seriously.

In 2010, the company 23andMe published a genome-wide association study on whether participants have “ever noticed a peculiar odor when you pee after eating asparagus?” This study pinpointed a single-nucleotide polymorphism (SNP) in a cluster of olfactory genes associated with the ability to detect the odor. While this SNP did not explain all of the difference in detection between people, it provides support for the theory that there are genetic differences in olfactory receptors that lead people to be unable to smell these odorous compounds. The onset of the asparagus urine smell is remarkably rapid. The smell has been reported to be detectable 15 to 30 minutes after ingestion.

Checkmate. If you can’t stand the smell of asparagus pee or the humiliation of passing it yourself in public, then continental northwestern Europe at this time of year isn’t for you. But for me, I’m going to make the most of it. Spargelsaison ends on June 24th, our stay here ends on the 21st, so for the next three and a half weeks I am going to take advantage of it and imbibe at any possible occasion vast quantities of that prince of vegetables, the asparagus, and may my urinary odour be but a burden on the olfactory senses of my enemies.