Cas sets his beer back on the table and it seems like he's going to get up. Dean doesn't want this to end, this warm and comfortable moment, so he splutters out the first thing he can think of.

"Are you hungry? I could eat!" Dean cringes internally. He’d just finished dinner half an hour ago. It sounds desperate to his own ears, but Cas just smiles fondly and shakes his head.

"Dean, you know I don't eat."

"Well, you don't need to, but you obviously do," Dean says. Cas's half empty beer bottle is proof enough of that.

"I can eat, but that is for social benefit. To celebrate a job well done," Cas says, fingers idly trailing through the condensation on the bottle, "Besides, I don't enjoy food the way I did when I was human. It all tastes too much like molecules."

It sounds like Cas wishes he could do something about it, so Dean instantly latches onto it as a problem to be fixed.

"Are there molecules you like the taste of?" Cas blinks in surprise as if the idea had never occurred to him.

"I suppose it's possible," he murmurs, "But I've never tried to find them. I imagine they'd all be about the same."

"Like how?"

Cas blows out a blustery sigh. "Oh, you know, too complex. Too many elements, long polymers chains, complicated folding patterns. It's all too much to take in."

"Then we'll find some simpler ones. Easy as that." Dean gets up and grabs Cas's hand, a tingle flashing over his skin where they touch. Cas opens his mouth to say something, but decides against it. He goes easily when Dean drags him out of his seat.

-

That's how they end up sitting on the kitchen floor long into the wee hours of the morning, surrounded by bottles and cans and boxes of every edible substance they can find. For each one Cas carefully scoops out a sample and passes judgment. He hates the texture of mayonnaise, honey is more intellectually interesting than gustatorily, coffee smells good and tastes horrible, et cetera.

They’d abandoned produce pretty early on after Cas decided that if he didn’t like broccoli, kale wasn’t going to be much different. The head of cabbage from Sam's side of the fridge is looking sad and wilted enough that Dean feels guilty about leaving it out. He hears Cas rustling around in one of the cabinets as he puts condiments and containers that failed the test back in their rightful places.

“Hey Cas, do you think–?” And he turns to see Cas wrist deep in a box of baking soda.

There is, of course, the space of time when Dean could say something. It’s not for eating, put it back, we’ll find something else. But Cas brings a dusty finger up to his mouth and carefully licks it, and a beaming smile breaks out across his face.

“Dean, I like these molecules!” he exclaims. There’s a smudge of white across his bottom lip.

“That’s awesome, Cas,” Dean says, because what else could he say when there’s a bigger smile on Cas’s face than he’s ever seen before?

Cas puts a fistful of baking soda in his mouth and laughs. Little puffs of powder leave his mouth with every exhale, like cold breath in winter.

Cas looks happier than he has in all the time Dean has ever known him. Over a leavener. Dean will buy a box for him every time he runs out. No, before he does. He’ll get those big four pound bags that no one ever buys. Dean will be the sole force standing between Cas and a baking soda-less life.

Just as Dean’s considering what becoming Arm & Hammer’s most loyal customer would entail, Cas extends the box to him and says, “Want some?”

Cas’s first instinct upon discovering a solution to a problem which had been bothering him for years is to share it with Dean. He feels absurdly like crying.

“Sure. Good for stomach aches, y’know?” Dean just says stuff sometimes, not even knowing if he means it. He takes a pinch between two fingers and immediately spills half of it down his shirt.

It tastes way worse than he thought it would. Dean just barely resists making a face as he tries to roughly swallow whatever hadn’t dissolved in his mouth.

“Salty,” he chokes out.

"Yes! That's the ions dissociating. Can you feel it?" His eyes are wide and bright. Fuck, are his cheeks a little pink? Dean's feeling flushed himself.

He lets himself cough just once before saying, "No, buddy, I think that's just a you thing." He longs for the dregs of the beer he left out there.

"Dean," Cas starts, staring down into his box, "Thank you."

"For what? You found it all by yourself." He wouldn't even have thought to suggest it.

"Thank you for giving me the push I needed to try," Cas says, a wry smile growing on his face as he looks up, "You always seem to do that."

If Cas takes Dean's impulses and crafts something better out of them, he's just happy to be part of the process.

"Anytime, Cas. I mean it. If I'd known that something like this could make you so happy," Dean inhales carefully here, "I'd have done it years ago."

Cas must get it because his eyes go wide and he stops breathing. He fidgets with his box. He crams another handful into his mouth.

"We should. Um. Get to bed. It's late, Dean."

"Yeah! Yeah. You'll... be here tomorrow, right?" Cas doesn't leave, doesn't wander the way he used to but it's always a possibility hovering around the edges of Dean's perceptions.

"I'm not planning on going anywhere, Dean."

-

And then that's how it goes. Sam finds Cas's habit funny. Jack joins in on it, though not with the same level of gusto as Cas demonstrates. There's always a box of baking soda in one of Cas's pockets, two if he's lucky. If Dean looks hard enough he can usually see a white streak of it somewhere on Cas's coat. His hands are often dusted with it like a baker's. If it feels gritty between Dean's fingers, who cares? It's what makes Cas happy and that's all that matters.

1.01 | 1.05 | 1.06 | 1.07 | 1.09 | 1.10 | 1.11 | 1.12 | 1.13 | 1.14 | 1.18 | 1.19

bonus: