Should we answer questions about biology, if they are food-related?

Question

There was a very long comments-discussion on an answer of Can you develop an immunity to chopping onions causing tears?, which triggered an automatic flag. I will delete the discussion from there, but the topic is interesting, so I would suggest that we continue the discussion here.

Content of the comments:

Eyes certainly do change as you age; it's plausible that something happens that's not specific to onions but still helps. – Jefromi♦ ↵ 19 hours ago

@jefromi Well, basic research indicates it is a reflex. I think anything deeper, and this is a medical or bio question, and no longer a culinary one. – SAJ14SAJ ↵ 19 hours ago

@Jefromi Can I ever attest to that! I'm blind as a bat, when the hell did this happen? – Jolenealaska ↵ 18 hours ago

@SAJ14SAJ I think we're quite happy to have biological/medical questions with culinary relevance here, just as we take plenty of chemistry ones. – Jefromi♦ ↵ 18 hours ago

@Jefromi Which is why I answered instead of voting to close as off topic.... but at some point, if we are going to investigate every chemical pathway and effect of the aging process, the culinary depth of the question will have been well exceeded. – SAJ14SAJ ↵ 18 hours ago

Here is a fun fact: syn-Propanethial S-oxide was the chemical of the week of the ACS: acs.org/content/acs/en/molecule-of-the-week/archive/… Who knew it was a celebrity! – SAJ14SAJ ↵ 18 hours ago

If the question's worth answering, it's worth answering completely. Maybe there's not an aging-related answer, but if there is one, I doubt it requires a ridiculously detailed examination of aging; it'd probably be a single physiological change that sometimes happens with age (maybe not for everyone). For example, some people end up with drier eyes. – Jefromi♦ ↵ 18 hours ago

@Jefromi That is an argument ad absurdem, otherwise every question would have to answered with the fundamental governing quantum mechanical equations. – SAJ14SAJ ↵ 18 hours ago

@SAJ14SAJ You are reading "completely" way, way too literally, making your resulting argument absurd. But it is no more ridiculous to say "aging eyes/tear ducts are often drier, resulting in less crying from onions too" than to say something about syn-propanethial-S-oxide. – Jefromi♦ ↵ 17 hours ago

@Jefromi: I rather disagree. An answer about syn-Propanethial S-oxide may sound a lot more obscure, but it's information about the onion. An answer about what happens to your tear ducts with age has nothing to do with food. – Aaronut♦ ↵ 12 hours ago

@Aaronut Fortunately we don't just answer questions about the fundamental properties of onions in isolation, we answer questions about humans using them in kitchens and eating them. – Jefromi♦ ↵ 12 hours ago

@Jefromi: The culinary use of onions does not encompass the effects of aging on human tear ducts. That's a question about biology, not cooking. – Aaronut♦ ↵ 12 hours ago

@Aaronut So you must think this question should be closed then. I would welcome an explanation on meta about this, especially if it makes it clear why this is bad but questions about taste perception and the nature of ingredients are about cooking (even if the explanations require chemistry or biology). – Jefromi♦ ↵ 11 hours ago

@Aaronut The answers (whatever they may be) come after the question. The question (despite the use of the word immunity) isn't a "health" question at all. It is a question about a completely normal (and perfectly healthy) response to a very typical culinary activity. – Jolenealaska ↵ 11 hours ago

@Jolenealaska No, I didn't really think there was anything wrong with the question. I just didn't agree that it was necessary or helpful to go into a series of hypothetical biological explanations about what might alter a reaction. This answer was at the appropriate level of detail, i.e. explaining the actual mechanism that causes crying from onions and how it might be a tolerance to the sensation but not to the chemical itself. – Aaronut♦ ↵ 10 hours ago

C'mon ... a 1999 article about onions? There was a group that showed that the process is not that simple, and even won this year's Ig Nobel for Chemistry – Joe ↵ 47 mins ago

Was 1999 a bad year for articles? Was it an uncredible source? Seriously, I read the new linked abstract (I don't have access to the full text), and while it expands the detail of the mechanism, it doesn't change anything fundamental--certainly nothing culinary, and nothing about the reflex reaction to the trigger of the tearing and burning sensation. Its import is that it might be possible to breed or engineer a tear-free onion, but that wasn't the point of the question. – SAJ14SAJ ↵ 44 mins ago

@SAJ14SAJ : see the Ig Nobel writeup : CHEMISTRY PRIZE: Shinsuke Imai [JAPAN], Nobuaki Tsuge [JAPAN], Muneaki Tomotake [JAPAN], Yoshiaki Nagatome [JAPAN], Toshiyuki Nagata [JAPAN, GERMANY], and Hidehiko Kumgai [JAPAN], for discovering that the biochemical process by which onions make people cry is even more complicated than scientists previously realized. The problem w/ 1999 is that it's dated, and been replaced with a more complete understanding of the process. (that there's other enzymes involved) – Joe ↵ 42 mins ago
upvote flag @Joe The ignoble site points back to the same abstract I already read. It may be slightly more complex, but it is not significant complexity in the context of this question, at least as described in the abstract. – SAJ14SAJ ↵ 39 mins ago edit

@SAJ14SAJ : but it still makes the part you quoted wrong. "The sulfenic acids, in turn, spontaneously rearrange to form syn-propanethial-S-oxide, the chemical that triggers the tears." They don't spontaneously rearrange, but are due to lachrymatory-factor synthase. – Joe ↵ 32 mins ago

@Joe Edited.... – SAJ14SAJ ↵ 19 mins ago

Answer 1

Yes, we should answer questions about biology if they're useful in a culinary way.

We answer questions about making food, including explanations of the reasons behind things, and sometimes we have to find those reasons in biology or chemistry. This is nothing new. This doesn't mean we should accept all tangentially food-related biology questions (e.g. "how do cow stomachs work?"), just that we should answer culinary questions, whether or not biology is required. And onions making you cry while you cook with them is a culinary topic.

• Why is meat red? (biology in the ingredient)
• Why are red wine glasses wider than white wine glasses? (chemistry/physics in the drink)
• Why do egg dye recipes include vinegar? (chemistry in the ingredient)
• Is it safe to cook wine or vinegar in cast iron? (chemistry in the equipment)
• Why is it dangerous to eat meat which has been left out and then cooked? (biology in the food)
• Why did butternut squash make my fingers dry and yellow? (biology in the person, though we never figured out the actual answer)
• What determines the 'saltiness' of salt? (physics/chemistry in the person - taste perception)

I could make the list longer, but I hope the familiarity of this kind of question is enough to demonstrate that they're commonplace. Some are chemistry, some are biology, some are about what's happening in the food, some are about what's happening in the equipment, and a couple even have something to do with the person doing the cooking or eating.

The question that set all this off is somewhat unusual in that it deals with the science of what happens to you when you're cooking. We often talk about what happens to you when you're eating (taste/perception). We often talk about the entire life of the the food (science behind ingredient selection and the entire cooking process). We often talk about the equipment used to accomplish things which may have scientific reasons behind them.

One of the things that's always made our site great is that we talk about the reasons behind things. The fact that onions make people cry is an everyday part of cooking. They clearly affect some people more than others, and asking why that is seems completely reasonable to me. We can talk about why some pans deal better with acid than others, why not why some humans deal better with syn-propanethial-S-oxide?

The "it's biology, not cooking" argument here, in my view, isn't a useful one. There's a set of topics we can discuss, and that's always included the underlying reasons. Sometimes they happen to biology or chemistry. What matters is the question itself. We cover everything from picking out your ingredients and tools, through all the things you do in the kitchen, to the nature of the finished product. If your question is about one of those steps, I don't care if you need biology or chemistry or astrophysics to answer it, it's on topic.

And as for this specific question, essentially "what factors would make someone more or less affected by onions?", I think it's totally fine. The question "how do I avoid them making me cry?" is absolutely culinary; it's part of cooking. "Why do they make people cry?" is part of that question; again, one of the great things about our site is that we don't just answer, we explain. And "Why do they make some people cry more than others?" is just a more detailed version of that question. It's not an extra step away, it's not non-culinary, it's just part of fully understanding. We can ask "why might my souffle fall one day but not the next?", or "why do cast iron pans (but not other pans) do weird things with acid?"; "why do I not cry when cutting onions?" is a very similar question, that just happens to have human biological reasons behind it.

Answer 2

When the topicality of a question is in dispute, when reasonable people disagree, I think it is always best to err on the side of allowing the question. I'm not saying that because the question in question happens to be mine, but because I think the issue is a pretty simple exercise in harm reduction. What is lost by closing a question that may have ultimately provided a fabulous answer is greater that what the site loses by allowing a "borderline" question.