Liu Tan has had oil to eat ever since he traveled to this world, so he has always ignored the most basic thing, soybean oil.

If Huo Guang had not been worried about the food structure problem in the northern border country, he probably would not have thought of this.

The food structure is a very serious problem, especially now that transportation is inconvenient. It costs a lot of money to buy food from other places, but others may not buy their soybeans. As a result, the basic livelihood of the people in the Northern Border Country is still not solved.

Therefore, we can only research a by-product, and then increase the value of soybeans by selling this by-product. After the value of soybeans is increased, there will be no problem of large price differences when "importing" food from other places, and the soybeans of the Northern Border Country will also have a sales direction.

Nothing compares to soybean oil.

Most of the oils nowadays are animal oils, and among the animal oils, only poultry such as chicken and duck, or more precisely, chicken, has the highest conversion rate.

Whether now or in the future, when fed with the same feed, chickens always produce more meat and oil. Although pigs and cows look huge in size, their conversion rate is actually much lower than that of chickens, especially since they are still fed with grains. Pigs need much more time to grow than chickens.

Then the question arises again. Feeding chickens also requires food. Nowadays, even food and clothing have become a problem in many places, so naturally chicken and chicken fat are unaffordable.

The existence of soybean oil allows people who cannot afford chicken oil to have a taste of the oil. From this perspective, the prospects for soybean oil are quite broad and cannot be compared with glass or something else.

It can't even be compared with coal. After all, some places can do without coal, but oil is indispensable.

Of course, the premise of all this is that he can produce soybean oil.

Probably no one except Liu Tan would have thought that soybeans contained oil, so he didn't say it in advance, for fear that others would think he was crazy. He could only sit in his study and remember how to squeeze soybean oil.

Yes, recalling the past, Liu Tan was one of the people who had witnessed the oil pressing process with his own eyes.

He was still young at that time, and every year when he went to his hometown in the countryside, he could see oil mills squeezing and selling oil.

The method of oil extraction in the countryside is certainly not very scientific, and the oil yield is not very high, but it is the most suitable for now.

After all, even if Liu Tan knew a more advanced method of oil extraction, he might not be able to do it due to lack of materials or machinery.

Before getting involved in soybean oil, Liu Tan reviewed all the current affairs. Well, Lin Xiu was in charge of the spring plowing, Xu Lin was in charge of digging lakes and canals, and Huo Guang was in charge of Tongda City. It seemed... it would be okay for him to be absent from work temporarily.

In fact, if Liu Tan had not come up with so many things, the operation of the entire Northern Border Kingdom’s court should be similar to that of Yan Kingdom.

Perhaps it will be smoother than Yan State, after all, Liu Tan will not be a drag.

Liu Tan instructed his subordinates to prepare soybeans and select the best quality ones, then put them into water to boil, take out the cooked beans and put them into a steamer to steam for half an hour, then spread the cooked soybeans evenly on a bamboo basket and put them into a humid and hot environment to ferment.

Originally, it was not easy to find a place for fermentation. First, the climate was dry, and second, the temperature was still a bit low. Liu Tan thought about it and directly asked people to put the soybeans in the greenhouse for fermentation.

After fermenting for one to two days, wash it with clean water, then soak it in hot water several times, and finally put it in a pot and boil it over high heat, then simmer it over low heat.

Finally, the juice inside is boiled into a thick consistency, which is soybean oil.

Liu Tan and his men worked in the kitchen for several days, but Huo Guang could not find him every time. Finally, on the fifth day, he saw Liu Tan and said helplessly, "Your Majesty won't come until after the summer solstice, which is at least four months away. Why are you starting preparations so early?"

Liu Tan was stunned for a moment: "What preparations are you making?"

Huo Guang placed the documents requiring his seal on the desk and asked, "Aren't you preparing special dishes for the emperor's arrival?"

Liu Tan felt ashamed after hearing this. He hadn't come up with any new dishes when Liu Che came before, but at least he still had the Changshou Palace to report to that time. As for this time... it might be difficult to come up with something new. He really needed to work hard in other areas.

He coughed lightly and said, "No, let's put this aside for now. I've been busy with other things these past two days."

Liu Tan turned to Miao Rui and said, "Go to the kitchen and bring over a bowl of what you made earlier."

Huo Guang originally wanted to wait for Liu Tan to sign before leaving, but when he heard this, he immediately sat there as steady as a rock.

Apart from anything else, what Liu Tan made was really delicious, and Huo Guang was even willing to come and serve as a taster.

Not long after, a young eunuch came in cautiously, holding a bowl. Liu Tan waved to Huo Guang and said, "Come, come and take a look."

Huo Guang smelled a smell from afar, a smell he had never smelled before. It was a bit like the smell of oil, but not quite the same.

He stood up and walked to Liu Tan's side, and what he saw was a bowl of dark yellow, translucent, thick liquid.

Huo Guang frowned slightly and asked, "Is this... oil?"

Liu Tan pointed at the bowl and said, "Guess what this is made of?"

Huo Guang pondered for a moment, then asked in confusion, "Could it be the artificial petroleum that Your Highness mentioned earlier, which was accidentally discovered?"

Huh? Man-made petroleum?

Liu Tan was stunned for a moment, then he remembered that he had indeed made it accidentally before. He shook his head and said, "Not that one. That one is also a good thing, but it's not easy to make."

At least no lives would be lost. If we use that method now, the whole group would be wiped out if we are not careful. Even if we are a little indifferent and think about it from the perspective of profit, he would have to pay funeral expenses and pensions for these people after they died, and he would also have to find new people to replace them. All in all, he would have to spend a lot of money!

This was too uneconomical, so he put the matter aside.

When Huo Guang heard that it was not artificial oil, he hesitated for a moment, stretched out his index finger, lightly touched a little, put it in his mouth to taste it, and it was indeed different from the oil he usually ate.

If you taste it carefully, you can find a faint bean smell.

Huo Guang looked at Liu Tan with some confusion and asked, "Your Highness... why does it smell like beans again?"

Liu Tan slammed the table and said, "It's made of soybeans!"

Huo Guang looked at Liu Tan calmly and said, "Your Highness, please do not deceive me. How can you get oil from soybeans?"

Liu Tan raised his chin slightly and said, "You don't believe me? This recipe is very simple. Just follow my instructions and I guarantee you'll be able to make it."

As he spoke, he took out a piece of paper and handed it to Huo Guang.

Huo Guang didn't even glance at it. He simply turned the paper upside down on the desk, took a deep breath, and said, "If this is true, Your Highness, you know this piece of paper is worth more than gold."

Liu Tan leaned on the table, yawned, and said, "I know, I still have other things I haven't taken out."

He pointed at the paper with his index finger and asked, "Is this a way out?"

Huo Guang knew much more about the prices of daily necessities than Liu Tan. After a quick calculation in his mind, he concluded that as long as the method was not difficult, soybean oil would definitely be much cheaper than chicken oil.

Huo Guang gasped: "This is not only a way out for the Northern Border Kingdom, it is a way out for the people of the Han Dynasty."

The entire Han Dynasty, not just the Northern Border, is suitable for growing soybeans, but millet is the main food. Once soybean oil is released, these places will no longer have to worry about millet. What's more... if the profit of soybeans is higher than that of millet...

Huo Guang thought a lot in an instant, his expression gradually became serious as he pondered how to promote such a thing.

However, the recipe is still in Liu Tan's hands, and he has to be careful about it being leaked.

Huo Guang said, "Your Highness, please don't leak this information for now. Let me think it over."

Liu Tan said, "Don't worry about it yet. I have a series of other things. Take a look at this. I wrote it before."

After Huo Guang took it, he found that it was a picture. No, it doesn’t seem quite accurate to call it a picture. Let’s combine the picture and the text.

If Huo Guang knew what a mind map was, he would understand what method Liu Tan used.

Liu Tan wrote the words "Soybean Economic Revitalization Plan" at the top, which made Huo Guang's forehead twitch.

Below these words are vertical lines arranged side by side. The first line is soybean oil, and the second line is other soy products.

There is a blank space under soybean oil, while the word "soy dregs" is written under other soy products. The term "soy dregs" extends to the left to form the word "feed".

Huo Guang was confused, vaguely understanding something, but still asked, "Your Highness, what does this mean?"

Liu Tan explained in detail, "This is very simple. Aside from using some of the soybeans we grow here as grain reserves, we also use some to make soybean oil, and some to make other soy products, such as tofu, bean skin, bean flakes, and dried bean curd sheets. When making these soy products, bean dregs are bound to form, and bean dregs are great for making feed. We use this feed to raise chickens, other poultry, and even pigs, and during the breeding process, they inevitably produce some... excrement. This excrement can improve the soil environment and improve the quality of the soybeans we grow."

Liu Tan scribbled as he explained, and at the end he drew a closed circle and said, "Don't you think this looks great?"

Huo Guang looked at the map, and it was undeniable that he was very excited at this moment. Every step here was clear and logical. As long as he followed this route, he felt that the revitalization of the Northern Border Kingdom was indeed just around the corner.

Before, they had been crossing the river by feeling the stones, and all the experiences recorded by the Han Dynasty seemed unsuitable for use in the Northern Border Country.

Liu Tan came up with so many things, and Huo Guang always felt that each one of them was very unique, but none of them was suitable. It seemed that only coal could truly benefit the common people.

But now he felt he saw hope.

Huo Guang took a deep breath, trying to calm himself, and asked the most crucial question: "That does seem good, but Your Highness... whether it's soybean oil or soy products, the Northern Border Kingdom certainly can't consume so much of these. So who should we sell them to?"