Cooking with Poison

The True Story of Poison Gas and Prepared Horseradish

Horseradish in Fall by Justin Brower

Horseradish in Fall by Justin Brower

Late fall is the perfect time of year to prepare horseradish sauce. Your horseradish plants have spent all spring and summer developing and growing delicious leaves (you’ve been snacking on those and throwing them into salads, right?), and now the first frost has appeared. Those tender leaves have died back and and the plant goes into survival mode, stockpiling sinigrin in the roots to protect itself from predators of the insect kind, and amping up its pungency.

What’s sinigrin and what does it have to do with horseradish? Shame on you. Shame, shame, shame. I already wrote about it here: Horseradish: A Chemical Explosion in Your Mouth. All the cool kids read it. If you somehow missed it, click the link. If you need a refresher course, look at the figure below.

Mechanism of sinigrin hydrolysis

Mechanism of sinigrin hydrolysis

So what we’ve got here is sinigrin, a glucosinolate, that when mixed with the enzyme myrosinase, hydrolyzes sinigrin, which then through a nifty rearrangement converts to allyl isothiocyanate. This is what gives horseradish its pungency and noxious aroma. Isothiocyanates are such Devilish things. But if we want to stop the process, we can add acid, like vinegar, and convert the aglycone intermediate (in brackets) to a safer allyl cyanide. Pretty simple, right? Who said organic chemistry was hard?

Horseradish by Justin Brower

Horseradish by Justin Brower

So what’s with the “poison gas” part in the title? Well, allyl isothiocyanate is a lachrymator that causes tears, corneal pain, and even naseau. And that pain is mediated by the transient receptor potential family of ion channels, specifically the TRPA1 receptor (1), which is closely related to TRPV1 of capsaicin and chile pepper pain. If you want to call it a tear gas or a chemical weapon, you might be a bit dramatic, but I wouldn’t stop you, I’ve got first-hand experience with it.

The time is late November and we’ve had a few light frosts. The horseradish leaves are dead or dying, and covered with fallen leaves from the overhanging hickory tree. So I round up my Dad, here for Thanksgiving, and the one intrepid daughter, of the three, willing to brave the cold, windy day, and we head out to the garden. I dig up the roots the best I can and hand them to my girl, who’s always happy to be in the garden with me. Check that, she’s always happy. My Dad? Not so happy. He’s grown accustomed to the nice weather of “God’s Waiting Room,” a.k.a. Florida. But he’s still out there, taking in the beauty of a half-dead plant and some scraggly roots. He’s looking forward to getting back inside, but if he knew what was coming, he’d have probably stayed outside.

Back inside the warm confines of the house, I cut off the tops of the horseradish roots, rinse off the dirt under water, and scrub them clean with a wash rag. The “typical” method of preparing horseradish is to grate or grind the horseradish with an equal amount of water, wait a few minutes for the allyl isothiocyanate to build up to the desired hotness, then quench the reaction with a tablespoon or two of vinegar. Throw in a pinch of salt, and you’re done. You’re always cautioned to do this in a well ventilated area or outdoors. But screw that. One, it’s cold outside, and two, and most importantly, I’m a Scientist.

Horseradish by Justin Brower

Horseradish by Justin Brower

So I take the roots and grate them on the smallest holes of that crappy cheese grater you see in the photo, and the result was a mild horseradish smell and flavor. I scoop it up and throw it into the blender jar of the Magic Bullet with a bit of water and blend away. Knowing I want my horseradish on the spicier, hotter side, I let it sit for about 3 minutes. With the lid still on. Doing so keeps all that allyl isothiocyanate goodness concentrated inside the jar. Is this a good idea? Of course not, but it’s OK, I’m a Scientist.

Giddy like a kid on Christmas, I gingerly unscrewed the base of the Bullet, carefully lowered my nose to within an inch of the open jar, and . . . inhaled deeply. The result was a bit worse than I expected. My eyes burned and teared up instantly, my lungs were scorched, and it was hard to breathe for a second, like I had the wind knocked out of me. A few moments after that, the nausea set in as I could sense a foul tasting burn from my esophagus to my gut. What came next was based purely upon instinct, carefully honed from decades of lab experience.

“Here, Dad, smell this.”

Chemists are trained to gently waft vapors toward their nose for a sniff. My Dad is a retired high school English and creative writing teacher – yes, I had him as my teacher my junior year – and not a chemist. He dove into the jar nose-first and inhaled a lungful of noxious horseradish gas. If this were a movie we’d be seeing a flashback to WWI trench and mustard gas warfare, but alas, it was just my kitchen he was dying in, coughing, hacking, and eyes watering. Don’t worry, he recovered just fine.

Why’d I do it? Because I’m not only a Scientist, I’m also kind of a dick.

Making Horseradish by Justin Brower

Making Horseradish by Justin Brower

I wanted to end this post with me being a dick, but there are obvious questions you all have:

  1. Is this true, and
  2. How did the horseradish turn out?

1. Absolutely. And I’m not even sorry about it. If my daughter had been there, I would have handed it to her instead of my Dad, but she’s smart, and bolted. My Dad? Not as smart. He made the mistake of trying to spend “quality time” with his son. This will teach him.

2. It’s good. Not spicy hot, but a great, natural, horseradish flavor. I think it benefits from sitting in the fridge for a few days as the flavors mingle and get to know each other.

So, horseradish is easy to grow and even easier to prepare, but just watch what you inhale . . . and don’t be a dick like me. I guess I did get the ending I wanted.

1. Brône, Bert, Pieter J. Peeters, Roger Marrannes, Marc Mercken, Ronny Nuydens, Theo Meert, and Harrie J.m. Gijsen. “Tear Gasses CN, CR, and CS Are Potent Activators of the Human TRPA1 Receptor.” Toxicology and Applied Pharmacology 231.2 (2008): 150-56.

20 thoughts on “The True Story of Poison Gas and Prepared Horseradish

  1. Very informative and very entertaining, thank you. I wonder how the need to quench the hydrolysis with vinegar was originally discovered?

    • Well that’s an excellent question. I wish I had the answer to it! I’ll try to look into it.

      My guess though is someone added vinegar (or similar acid) as a preservative, or to make a similar mustard, and noticed the difference in pungency from various batches.

      • `I make a sauce by adding mayonaise, Dijon mustard, vinegar to grated fresh horseradish, keeping it in a jar in the fridge. I have seen it last for months and months, and never seems to go bad, never molds, etc. Why is that?

        • Most likely the acidic environment, from the vinegar and mustard. Thanks for reading!

    • This post made me laugh so hard. It was indeed medicine for my spirit.

  2. Pingback: Horseradish: A Chemical Explosion in Your Mouth | Nature's Poisons

  3. There seems to always be someone at the Passover seder meal who can’t resist eating chunks of horseradish instead of the grated root that has been exposed to air. Talk about bitter herbs! It’ll clear your sinuses all the way up to the roots of your hair!

  4. Pingback: Blogroll: Tasty chemistry : The Sceptical Chymist

  5. Pingback: Nature's Poisons - The Garden Professors™

  6. I found a similar effect when I was preparing horesradish in my Magic Bullet the other day. I was expecting the onion-like burning in the eyes, but the scorched feeling in my lungs was surprising! I even smelled it from a few feet away.

    I wasn’t using a grater, just 2-inch chunks of horseradish root and the bullet. The hard part was opening and closing the bullet again and again to check that the chunks were fully grated, and then, rounding it all up by spatula to put into jars.

    It seems like every time I stirred the mixture, a new cloud of the gas came out! I kept on stirring it into a jar, while holding my breath, and then running back outside to “let it air out” for a few minutes, before going back in. I eventually found a technique where I stopped even facing the jar towards me, watching the spoon and the grated root through the clear side of the Bullet as I poured it into the jars.

  7. Pingback: The Trouble with Thistles | Nature's Poisons

  8. Pingback: Nature’s Poisons – The Garden Professors™

  9. That was indeed dickish of you. Onions are bad enough when being cut.

  10. I always make my horseradish sauce in the nutra bullet. wash it chop it . stick it in with a little water. blitz completely. add mayonnaise salt and vinegar and blitz again. it’s wonderful really takes people by surprise. love your story. I used to ware a respirator and swimming goggles but I’ve manned up now. just don’t stick your face in it. and any splash will burn your skin. 🙂

  11. hahah! that is a great story! I have certainly gassed myself on occasion making it. My husband is too smart to fall for that though.

  12. Hey Justin, here’s something I’m hoping you can help us answer, What reaction happens when you mix horseradish and vodka?
    My boyfriend had a horseradish cocktail at a Russian bar once and said it was delicious. In attempting to make his own, he prepared the ingredients based on a recipe he found online: 35g of radish to 375 ml of vodka. The radish is blended heavily in a blender with the vodka and then the drink is filtered through a coffee strainer. We left it straing for about an hour and then it was put in the freezer for about an hour and a half.
    After dinner, we pulled out the drink. The result was a cocktail of sheer panic. No more than two minutes after taking a sip, you feel what you think is heartburn, however it quicky turns into a feeling of dread, anxiety, and panic- all central to the horseradish drink making its way down your esophagus. I’ve had panic attacks before and I’ll say it freaked me out – I thought maybe I was having an allergic reaction because it feel like it was inducing one. Before I even mentioned it to my boyfriend, he started pacing around the room saying “this is bad- what’s happening? I feel like I did in highschool when I had to take a test I didn’t study for…” And then my other housemate took a sip and chimed in with “oh yea this is unlike anything I’ve ever experienced- I’ve never had anything I’ve digested induce a feeling of anxiety!” He’s a nurse and thinks it has something to maybe do with histamines …
    So here we are. Hoping you can shed some light on this for us! … what do you think?

    • Off the top of my head, I have no idea. People make horseradish vodka all the time. A lot of recipes I’ve seen call for some sort of acid to drop the pH, like lemon juice, to push the reaction to the allyl cyanide and away from the more noxious ally isothiocyanate. I saw your preparation doesn’t have an acid component, but honestly, I see it producing something more distasteful, not anxiety-producing.

      • Ok, noted. Thanks for noodling in it! I guess it will forever be a mystery.

Leave a Reply to Justin Cancel reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s