Rapeseed needs to be dried promptly after harvest to prevent spoilage. When drying, it should be spread thinly and turned frequently to ensure even drying and prevent mold growth in storage.
This year's rapeseed harvest from over ten mu of land yielded only about three thousand jin. Chen Lan decided against using the multi-functional grain screening machine to remove impurities, as the rapeseed kernels were too small and she feared unnecessary waste. Instead, she asked Uncle De and the elders to use traditional methods for impurity removal.
The weather was good during this period, with plenty of sunshine and wind, so the rapeseed dried quickly, in less than two days.
Upon arriving at the drying ground, Chen Lan saw Uncle De scoop a handful of rapeseed into his palm, tilt his hand upwards, and let the seeds slowly fall through his splayed fingers.
Chen Lan was surprised that Uncle De, at his age, still enjoyed playing children's games. As she pondered this,
Uncle De noticed Chen Lan's arrival and clapped his hands. "Xiao Lan, you're here. The rapeseed is dry and reasonably clean now. We can put it into storage. What do you think? Should we store it all, or store some and press oil from the rest?"
Only then did Chen Lan realize Uncle De wasn't playing but was actually assessing the quality of the rapeseed for oil pressing.
She then asked, "Uncle De, do you know the oil yield of rapeseed?"
Uncle De replied with a chuckle, "Xiao Lan, I do know that. We even ran an oil press in good years. For every hundred jin of rapeseed, we can press about thirty to thirty-five jin of oil. It depends on the variety of rapeseed, as different varieties have different oil content. Moreover, we are growing spring rapeseed, and it's an early-maturing variety, so the oil yield will naturally be a bit lower!"
Chen Lan estimated that the over three thousand jin of rapeseed harvested from ten mu this year would yield about a thousand jin of oil. This should be enough for the people in the valley for a year. If there were any shortages in the last month or two, she could supplement it. Next year, if they planted another five to ten mu of rapeseed, it should be enough for everyone in the valley.
She said regretfully, "Alas! It's a pity. Changbai Mountain is too cold, so we can only plant spring and early-maturing varieties. We don't have any better options, so this is how it has to be for now."
Uncle De smiled and said, "Xiao Lan, don't be discouraged. I've examined it closely, and the rapeseed harvested this year is plump. The oil yield shouldn't be low. I estimate we can press at least forty percent oil."
Upon hearing that more oil could be extracted, Chen Lan immediately became excited. "Uncle De, let's press all of it! That way, it won't attract insects in storage. I've already prepared the oil press and barrels; they're in the tool shed. We can start pressing oil right away."
Uncle De said with a smile, "You are quite impatient, child. I haven't finished speaking. We can't press oil yet. We need to wait until after the rice harvest. We'll use some rice husks when we press the oil."
Chen Lan asked in confusion, "Uncle De, what does rice husk have to do with pressing rapeseed oil?"
Uncle De explained with a smile, "It's to extract more oil. This is an old family secret from Old Zhang at our oil press. When pressing oil, adding some coarse rice husks to the rapeseed slows down the sliding speed of the seeds, allowing them to rub and generate more heat, thus extracting more oil."
Chen Lan thought to herself that the wisdom of the working people was truly remarkable! Despite their lack of formal education, they understood principles akin to generating electricity through friction.
This was the same principle behind stir-frying and heating rapeseed before pressing, as oil molecules are most active at higher temperatures, making it essential to press the oil while it's hot. The friction between the rice husks and the rapeseed also generates heat, which is the reason for the increased oil yield.
As Chen Lan and Uncle De were discussing oil yield, Grandpa Xu and Grandpa Li approached. Grandpa Xu said urgently, "Xiao Lan! My friend Li and I just checked the peanut field. The peanuts are mature, and we should start harvesting them."
He then extended his hand, offering Chen Lan a handful of wet peanuts, presumably freshly picked from the field.
Chen Lan took them and observed that the peanut veins were clear and distinct. She squeezed them; the shells were quite hard. She shelled one and saw that the kernels were plump. The peanuts were indeed mature.
She replied with a smile, "Grandpa Xu, don't worry. We will harvest the peanuts sooner or later. I'll arrange for people to harvest them as soon as I finish here."
Grandpa Li said unhurriedly with a chuckle, "Xiao Lan, it's not that your Grandpa Xu is impatient. We are in a hurry for a reason. Firstly, if the peanuts are harvested late and left in the soil, they can sprout. Secondly, the peanut pods can easily fall off, affecting the harvest yield. Thirdly, the rats and other small animals in this valley are very troublesome and spoil quite a few peanuts every day."
Upon hearing Grandpa Li's explanation, Chen Lan immediately became serious. How could she forget about the rats in this valley? These troublesome creatures seemed to be everywhere, and they were a real headache!
Without further delay, she entrusted the rapeseed to Uncle De and agreed, "Grandpa Xu, Grandpa Liu, please wait at the drying ground. I'll drive to harvest them, and we'll have the peanuts back in no time."
With that, she strode towards the garage. On the way, she met Lin Mai, who was returning with a tractor. She immediately called out, "Mai, you don't need to return the tractor. Attach the rear trailer and bring the plowing attachments. We're going to the peanut field to harvest. Wait for me here; I'll go get the peanut harvester."
Lin Mai quickly said, "Sister Xiao Lan, please rest for a while. I'll go. I want to drive the peanut harvester. I'll bring the trailer and plowing attachments for you."
Before she finished speaking, she had already run off.
Chen Lan and Lin Mai had collaborated many times before. They worked together seamlessly, quickly, and efficiently. The peanuts from over ten mu were harvested in less than two hours. Chen Lan made two trips to the drying ground, estimating about two thousand jin each time, for a total of roughly four to five thousand jin.
The remaining task was to deep plow the ten-odd mu of peanut fields, which she could do by herself at her own pace. Chen Lan then told Lin Mai to go back and not wait for her, as cleaning the peanut harvester took some time.