"Hmm, this is difficult..."
Jin was currently racking his brain to fulfill the request he had received from the Empress of the Shouro Empire. Specifically, he was working on the insulation barrier.
"Jin-nii, didn't you say you could finish it right away when we talked before?" Elsa asked, her tone carrying a sharp edge of skepticism.
"Yeah, I did. But the more I thought about it, the more features I realized I wanted to add."
"Features?"
"Exactly. For example, take that tempura from the other day. Even if it doesn't get cold, the oil eventually soaks in and ruins that crispy texture..."
Elsa understood his point immediately. The light, crisp batter of freshly fried tempura was its greatest appeal; once the oil saturated the coating, the experience was ruined.
"I see what you mean."
"And since this is a gift for Her Majesty, I thought about layering a sterilization barrier to prevent food poisoning, but..."
"But?"
"I also started wanting to add a poison detection function."
"Jin-nii..."
"Well, she is the Empress. I can't help but worry about what she's putting in her mouth."
"I suppose I can't blame you for that, but still..."
Elsa looked at him with a mix of affection and exasperation. Jin was always one to get obsessed with the details.
"So, I've been agonizing over it."
"...I understand. I'll help you."
Exasperation aside, Elsa knew the barrier Jin was envisioning would have a massive range of practical applications. As someone who frequently handled food, she saw the undeniable value in it.
"Let's start by organizing our tasks. The sterilization barrier is fine as it is, right?"
"Yeah."
"The insulation part shouldn't be a problem either."
"Right." That part had been essentially finished when the idea first struck him.
"So the oil issue and the poison detection are the only things left."
"That's about the size of it."
Having everything laid out made it easier for Elsa to process as well.
"As for the poison... I think it should be easy enough if we focus on specific substances."
"I thought so too. Arsenic, mercury, lead—the usual suspects."
The real challenge lay in detecting unknown toxins. If they were dealing with the human body, it would be relatively simple. The goal would be to detect and exclude any substance that didn't naturally belong there. That was exactly how Detox accessories worked. However, when it came to complex dishes, you couldn't just strip everything out.
"Basic elements are one thing. Like the lead and arsenic we mentioned."
However, elements like copper, chromium, and iron were necessary minerals for the body in trace amounts. They only became harmful if the concentration was too high. For instance, trivalent chromium was vital for sugar metabolism, whereas hexavalent chromium was a toxic carcinogen.
"I'm starting to think we should just stick to the same specifications as the Detox accessories," Jin said. "We can use the human body as the baseline."
"...Mm. This isn't meant to be a dedicated detox device, so I think that's for the best. You shouldn't mistake the means for the end, Jin-nii."
Jin took her words to heart.
"Yeah, you're right. I got greedy and lost my way. Thanks, Elsa."
With his doubts cleared, Jin decided to treat the detox function as a mere bonus.
"Now, about the oil."
The request had originally come from the Empress's comment about how cold tempura lost its charm. Oil-soaked tempura was just as disappointing. Jin wanted to address this head-on.
"Oil soaking into the food is a physical change, while the flavor turning rancid due to oxidation is a chemical one."
"Mm."
In theory, both could be halted if they lowered the temperature to absolute zero.
"...But we can't do that."
"No, we can't."
That would defeat the entire purpose of an insulation barrier.
"...Let's think about how to slow down the movement of atoms and molecules."
"Mm."
Elsa had a solid grasp of science at a middle-school level, which gave her plenty of foundation to help tackle these technical hurdles.
"Stand Still?"
"That's a bit much for me," Jin admitted.
He hated using the word "impossible," but he knew he couldn't achieve true temporal stasis overnight. This was supposed to be an extra for a food storage device, after all.
(Still, it’s an interesting concept to keep in mind,) he noted silently.
"Could we just slow things down?"
"Hmm, let's see."
Jin pondered for a moment. He thought of the magi-device known as the Ether Stocker. When mana-conductive materials were placed inside it, they could be preserved almost indefinitely.
"The principle there is that free ether fills the gaps between atoms, hindering the movement of magiatoms. I wonder if it would work on normal atoms as well?"
They decided to put the theory to the test. They placed a block of ice inside an Ether Stocker and applied heat.
"Wow. It's definitely melting slower."
It took roughly five times longer than usual.
"If we combine this effect with the insulation barrier, we’ll have something truly impressive."
"An insulation barrier... or maybe a preservation barrier?" Elsa suggested.
"You're right. A preservation barrier. Now we just need to figure out how to package it."
To start, the duo created two versions: a preservation storage unit about the size of a standard household refrigerator, and a preservation tray for short-term use.
"Let's present these to her."
They could always make adjustments based on her feedback later.
"Oh my! This is marvelous, Jin-kun!"
When they reported their success and presented the samples, the Empress was absolutely delighted.
"It took a little while, but I hope this meets your expectations."
As Jin explained the various functions, her excitement only grew.
"Yes, yes! This is wonderful. You call these 'extra features' out of modesty, but a barrier that prevents spoilage and another for detoxing? These are national treasures!"
"I... thank you very much."
Jin felt a bit sheepish under such lavish praise.
However, the true test came from the palace staff. After the kitchen crew used the devices and realized their incredible utility, they practically begged for more. Just five days later, Jin found himself converting an entire room in the Kitchen Wing into a massive preservation storage unit.