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- What's a great way to get moist, tender food that's not over cooked? I'm joined by a special guest today as we look across cultures at the science of steaming. Hi, I'm Julie and welcome to Hungry for Science. Today I'm joined by a very special guest as we both each explore some foods from our cultures. This is Dr. Isabel Hawkins, who is an astronomer, salsa dancer, a food enthusiast. Welcome Isabel, and let me know what you brought today.

- Thank you so much Julie for having me today. Welcome to the program. I brought for you today my favorite Argentinian traditional food called humitas.

- And tell me a little bit about them.

- So here's we have an example of a humitas that has just been steamed and you can see it looks probably very familiar to you. It might look like a tamale, or tamale as we say here in America. And we're gonna just take it apart. You can see that it's wrapped in the corn husk. And what's interesting about this is that because it is made with fresh corn, as opposed to corn masa, it has a little bit more of a pliable texture. It's a little bit more like a sweet pudding. And as a matter of fact it is really sweet because it's made with fresh corn. How about your beautifully wrapped food?

- I am unwrapping a Chinese zongzi. This is also a little steamed bundle, but inside there's sticky rice, and I have some pork and mushroom filling inside. This is a food that's traditionally eaten at the dragon boat festival.

- Ah, interesting.

- And I'm gonna taste them both and see what we think.

- Yeah I'm gonna unwrap yours too, let's see. Really easy to pull out of their beautiful plant wrapping. Let's try this out. I'm gonna try yours first. Mm, absolutely wonderful. Very tangy. And it contrasts nicely with a sweet of the humitas.

- Yeah, very different flavorings, but very similar texture. They are both, both moist and delicate.

- Absolutely.

- And so tell me how you make these.

- So you basically get fresh corn and you either shred it or you cut it from the cob and you might put it in a blender with some sweet red pepper, onion, and garlic, and you saute everything. And then you basically will stuff the corn husk that has been previously soaked, and then you make your little packages and then you steam them.

- Zongzi are made very similarly. They start out, you need to soak your bamboo leaves. And once they're soaked they're very pliable. If you can make a little cone, put your sticky rice that's been soaked and filling in, and then you fold it up until you get this nice kind of classic tetrahedral shape.

- That's wonderful. And you know what I found too is that, you know, if you just tear the husk apart, it's amazing how resilient and strong this is. I was able to make, you can actually try it, but also probably with bamboo, I was able to make this little ties and look how strong they are, very resilient. And so everything is done with the same leaf.

- You know people do the exact same thing with zongzi where they'll take a little bit of the bamboo and use that to wrap. I've used string but this is a much more eco-friendly way to wrap your zongzi. So both of these are steamed and that actually allows them to slowly cook without over cooking, by being wrapped in this plant material. This is water resistant, but not waterproof. It can absorb water. And then some of that water will condense and be delivered into the starches, either the corn or the, the rice. But it's, it's a real gentle way to cook. Some people boil zongzi but I really prefer to steam it, even though it takes more time because the flavor doesn't leach out into the water, it stays inside the nice package.

- Yeah, indeed. I think that one thing that I found last night as I was steaming them, is they also have to be very careful because steam can actually burn you more than hot water because the molecules are moving so fast, so they carry more energy. So you have to be really careful when you uncover and pull them out.

- Yeah, that's exactly, exactly right. So water boils at a hundred degrees Celsius and steam will stay at that temperature, but the heat transfer as it moves and condenses onto your food can just transfer a, a tremendous amount of energy.

- Definitely, definitely. But these are absolutely delicious. And what I've enjoyed is that I hadn't made these for a long time and it reminded me of my childhood or reminded me of eating traditional foods, listening to my traditional music at home. And it really brought some good memories and I appreciated this opportunity.

- I will say that these are a little time-consuming to make. And so people usually make large batches and I believe the same is about, the same happens for humitas. So what's your favorite way to reheat leftovers?

- Yeah well, if you have kept one of these, you could just wrap it together again, or you can just basically take a moistened paper towel, wrap your humitas in one of these that has been in the refrigerator. You just wrap it with a moistened paper towel, zap it in the microwave and you got your favorite snack very ready to eat.

- You know I do the exact same thing with zongzis by wrapping them in a little paper towel, in a wet paper towel, it basically creates a small steaming chamber. And your microwave is actually a great tool to steam. So if you are interested in some delicious, moist food, make sure you wrap it in some water resistant material and heat it by steaming. And maybe your family makes something that looks like this too. It might look like either one of these foods or something else. Let us know in the comments. Thank you so much for being here Isabel.

- Thank you.