Chapter 343 - Sweet Potato Kvass

Whether the common people of Ming Dynasty Guangzhou would actually purchase this Liancheng Red Heart Dried Sweet Potato Strip—appearing centuries ahead of its time—remained an unknown variable. But Wu Nanhai felt that selling dried sweet potatoes, such a relatively simple product, was beneath them as a money-making endeavor.

"Dried sweet potatoes can be one option," Wu Nanhai conceded, "but the processing depth is insufficient. The added value is too low."

"The problem," Mo Xiaoan countered, "is that Ming Dynasty commoners don't need starch. Who would we sell our starch production to?"

"They don't need it—but we do." Huang Dashan smiled enigmatically. "Forget industrial demand for a moment. Starch alone could substantially improve our meals. It's the starting point for many products."

The others instinctively edged away from this mysterious figure, whose very presence seemed to exude invisible clouds of microorganisms—bacilli, viruses, and stranger things. In truth, ninety-nine percent of Huang Dashan's biochemical laboratory contained useful strains: various mushrooms, fungi, and an array of fermentation cultures preserved in growth media.

"There's one product that satisfies your export ambitions while also improving everyone's meals," Huang Dashan continued. "MSG. I have specialized strains. The quality will be excellent."

"Doesn't MSG require rice to manufacture?"

"Rice certainly works; what matters is the starch. Sweet potatoes, potatoes, anything starch-rich will do. Nothing unusual about it." Huang Dashan pressed on: "Cooking wine, vinegar, soy sauce, bean paste—all the condiments we used to make with rice. The food factory's production was limited before mainly to conserve grain. Now, with sweet potatoes providing cheap bulk starch, we simply need to scale up directly."

Shi Niaoren mentioned his glucose injection plan. Wu Nanhai expressed strong support, telling him to make as much as needed. Shi Niaoren clarified that current requirements were modest—a few kilograms would suffice.

"Glucose injections don't require much."

Though glucose injection was useful, it wasn't an urgently needed drug; its presence or absence made little practical difference. Shi Niaoren's eagerness to produce it was partly about demonstrating the pharmaceutical factory's value—after the Executive Committee's substantial investment, they couldn't spend all their time mixing oral saline to show for it.

"The oral physiological saline and herbal tea you've been producing are quite good," Wu Nanhai observed. "Make more of those. The weather's been hot lately; they're in high demand."

"Actually, I wanted to make salt soda water." Shi Niaoren sighed. "Carbonated drinks are the ultimate thirst quenchers. But there's no baking soda available."

"Soda water is wonderful—a fashionable favorite—" Mo Xiaoan seemed ready to launch a soda water marketing campaign for Ming Dynasty consumers.

"Baking soda soda water?" Wu Nanhai scoffed. "I mixed that according to recipes when I was a kid—tasted terrible. Complete failure. Spare us. I heard Superintendent Ma designed a soda machine? It doesn't use baking soda—it dissolves carbon dioxide directly into the liquid."

"True, that's possible—he just copied historical designs. But where do we find high-purity carbon dioxide? I'm told we have fewer than twenty pressure cylinders of all sizes. Soda water production is definitely not a priority."

Huang Dashan laughed. "You people are thoroughly modern—you only think in terms of chemical preparation and physical processing. Forgotten about microorganisms? Where does Champagne get its bubbles? What about beer? They're not made by adding baking soda or pumping in carbon dioxide."

"You mean brewing beer from sweet potatoes?" Wu Nanhai's mind moved quickly.

Huang Dashan nodded. "Beer requires malt, and we're short on both wheat and barley. Otherwise, Banana from the Special Reconnaissance Team would have started brewing long ago. I've never heard of making beer from sweet potatoes." He winked. "But I can make Kvass."

"Kvass?!" Several voices exclaimed in unison. This was something exotic.

They had all heard of this beverage, wildly popular in Russia and Eastern Europe. Fermented from dried bread, Kvass was nearly beer-colored but with a reddish tint, moderately sweet and acidic, with a distinctive fragrance, abundant carbonation, and extremely low alcohol content. It was a soft drink beloved by the masses.

Traditional Kvass was fermented from bread. But Huang Dashan knew that some modern factories, seeking to reduce costs and production time, skipped the bread step entirely. They fermented starch-rich raw materials directly, adding natural or synthetic aromatics to compensate. He had previously helped a boss in the Northeast develop a sweet potato Kvass fermentation process.

"Kvass is far more impressive than soda water!" Mo Xiaoan declared. "The Ming Dynasty has plenty of wealthy people. Kvass could target upscale female consumers."

"I think having enough for ourselves to drink would be achievement enough," Wu Nanhai said drily. "Will it work?"

"Making Kvass from sweet potatoes is a technology developed in the 1990s." Huang Dashan was confident. "The process is simple. The drawback is it lacks the bread aroma of traditional Kvass, and we don't have synthetic essences here, so we'll need to add other things artificially."

"How do you seal Kvass? We don't have a soda bottle capping machine, nor tinplate for bottle caps. It's a carbonated beverage."

"However Champagne is sealed, Kvass can be sealed the same way." Huang Dashan shrugged. "Cork stopper, tightened with wire outside, plus wax seal. Champagne bottles hold much higher pressure. I haven't seen the capping machine, but presumably it's not high-tech—it can be built eventually. Tinplate just requires iron and tin, which should be manufacturable."

"What equipment do you need?"

"A few large vats will do." Huang Dashan had clearly thought this through. "But I need guaranteed allocation of various culture materials—strain and enzyme demand keeps growing, and there are gaps in equipment and media."

Unlike traditional Kvass production, Huang Dashan's process was streamlined. First, sweet potatoes were peeled and ground into slurry, then mixed with water to seventy-five percent moisture content. Monitoring the thermometer, he added a small piece of something resembling culture medium.

An hour later, he added another piece of similar material. At intervals of thirty to sixty minutes, he introduced additional suspicious-looking substances. Throughout, he constantly directed the stoker to add or reduce fuel, maintaining precise temperature control.

"What are these?" Wu Nanhai finally asked.

"Various enzymes." Huang Dashan replied. "Cytolytic enzyme, pectinolytic enzyme, several amylases..."

The sequentially added enzymes decomposed all dextrin in the sweet potato slurry into sugar.

Next came fermentation. He continued adding suspicious substances—this time, proteolytic enzyme.

Wu Nanhai watched him inoculate, heat, add water, heating again—bustling about with evident satisfaction—but felt increasingly suspicious about what exactly was happening. Huang Dashan looked less like someone producing a fermented beverage than a mad scientist mixing potions.

Finally, after boiling, cooling, and filtering, Huang Dashan carefully poured culture fluids from two separate tubes into the filtered juice.

"Brewer's yeast and Lactobacillus delbrueckii culture fluid."

"Yeast I understand, but will this Lactobacillus cause problems?" Wu Nanhai remained wary of anything ending in "bacillus."

"No problems." Huang Dashan offered no elaboration. He instructed the stoker to maintain the liquid temperature at a constant 26°C for gradual fermentation. "Filter and bottle after sixteen hours of fermentation, sterilize using the Pasteurization method, then let it rest a few days. Once it produces foam, the Kvass is ready."

"That's it?" Wu Nanhai felt thoroughly confused. The process bore no resemblance to what he had imagined.

"That's the power of bioengineering." Huang Dashan said proudly. "This is just a trial batch. Given proper resources—natural essential oils, fruit juice, honey, citric acid—the taste would be considerably better."

"Citric acid really is wonderful stuff. Canned food and soda water both require it. If only the Chemical Department could produce some." Wu Nanhai reflected that citric acid also had water purification, disinfection, and sterilization properties; adding it to livestock feed could increase protein digestion efficiency and improve feed utilization.

For the food processing factory itself, citric acid was desperately needed as an acidic flavoring agent in beverages, soda water, candy, pastries, biscuits, canned goods, and dairy products. It also served as an antioxidant for edible oils—the soon-to-launch coconut oil pressing project would require it.

Huang Dashan looked unimpressed. "What does that have to do with the Chemical Department?"

"Doesn't citric acid come from chemical plants?"

"Citric acid is produced by fermentation," Huang Dashan said. "Submerged fermentation of dried potato powder for citric acid—that's a uniquely Chinese technology. I have the strain."

"And we have the sweet potatoes!" Wu Nanhai exclaimed.

"I'll need a fermentation tank built." Huang Dashan nodded. "I don't believe the Planning Committee brought specialized fermentation tanks. They're not high-tech; carbon steel construction should be straightforward."

Thus, production of Kvass and MSG was added to the agenda. Wu Nanhai and Mo Xiaoan discussed the matter further, consulted materials in the Grand Library, located several sets of architectural designs and equipment drawings for indigenous sweet potato processing enterprises, and submitted them to the Planning Committee for approval. Approval came back quickly.

Mo Xiaoan brought the equipment requirements and drawings to Jiang Ye. Jiang Ye studied them briefly: the design was almost entirely wooden. Except for shafts and grinding blades, which were iron, everything else was wood—including transmission rods and gears.

"Where did this come from?"

"Great Leap Forward era commune sweet potato processing factory drawings from the Grand Library." Mo Xiaoan said. "Almost no steel required. Nearly all wood. Saves material, easy to fabricate."

Jiang Ye shook his head. "To put it politely, this is an emergency substitute. Frankly, it's window dressing for inspecting officials." He pointed at the sweet potato washer's structural diagram. "All-wood mechanism roller, hardwood lever, wooden gear... Did the designer consider material strength? And it's hand-cranked. Hundreds of jin of sweet potatoes plus a pool of water—even the Governor himself couldn't turn this thing." He continued examining the drawings. "If we build this, the whole setup will collapse within days. Build it from red sandalwood and the result would be the same."

"So it's not feasible?"

"The structural design is fine, but the materials need changing." Jiang Ye began scribbling notes. "I'll have to redesign it."

"How long?" Though Mo Xiaoan wasn't from the Agricultural Committee, he knew sweet potatoes couldn't wait.

"At least a week." Jiang Ye studied the drawings further. "Engineer Wang held a mechanical manufacturing standardization meeting. All specialized processing equipment must now use standardized materials and process flows. Sweet potato processing systems are no exception. So: redesign. Materials, performance—everything needs comprehensive consideration. We can't just prioritize material savings. And you'll need a prime mover. Otherwise this machinery won't run. Don't believe these flowery Great Leap Forward pamphlets—most of what's in them was designed to fool inspectors."

"I'll apply for a steam engine—might as well get a boiler too."

"No need. Apply for a single-cylinder diesel engine. This equipment can be driven by ten horsepower. Don't think about steam engines and boilers right now—riveters are in short supply. Zhou Bili and his apprentices are all building ships. When they'll have time for boilers is anyone's guess."

"Diesel means applying for diesel allocation—" Mo Xiaoan hesitated visibly. Diesel was precious; the sweet potato processing project would never qualify for a diesel quota.

"Use coal gas." Jiang Ye began promoting the Industrial and Energy Committee's new coal gas generator.

This new generator had been developed under Wang Luobin's direction, primarily to utilize the large inventory of single-cylinder diesel engines on hand. Additionally, the diesel engine factory project he was personally overseeing was moving into implementation.

Single-cylinder diesel engines were low-tech. As the machinery factory's supporting workshops—especially the foundry—came online, and apprentices in this timeline grew more skilled, manufacturing these engines was no longer a fantasy. Compared to steam engines, single-cylinder diesels offered enormous advantages in size and fuel efficiency. The drawback was equally obvious: no fuel. The Transmigration Group was severely short of both diesel and vegetable oil alternatives.

For the foreseeable future, neither would be abundant. Thus the coal gas generator—that artifact of petroleum-scarce eras—came to mind.

Coal, at least, they wouldn't lack. Even without coal, straw, wood, and charcoal remained available. Supply worries were minimal. Furthermore, coal gas could power diesel and gasoline engines directly with only minor adjustments. This meant modern vehicles brought from the other timeline could continue operating after installation of coal gas generators—at least until the Transmigration Group could develop petroleum resources.

Coal gas generators did reduce engine power output, but Germany had installed similar devices on half-track armored personnel carriers near the end of World War II. Reportedly, even the nearly fifty-ton Panther tank had been experimentally fitted with coal gas generators. Power impacts should be manageable.

Wang Luobin had designed several coal gas generator variants. One compact type was specifically configured for vehicles. Another was a medium-sized complete system designed for industrial applications, using a flat-suction principle. Though structurally more complex, this furnace could accommodate low-grade fuels.