WWW.WA S .ORG • WORLD AQUACULTURE • SEP TEMBER 2022 47 ( C O N T I N U E D O N P A G E 4 8 ) oil could ruin the harvest for the day. The nori produced monospores from the sides of the plant that settled on the nets, resulting in multiple generations and different lengths. This allowed each net to be harvested several times, with new tender blades mixed in with older, tougher blades. This resulted in the first harvest having the best quality and each subsequent harvest tougher. This had to be compensated for when the nori sheets were made. CPI purchased the equipment to process nori into sheets. This included several machines – a centrifuge to remove excess water from the harvest, a chopper/grinder (Fig. 9), slurry maker, sheet maker and dryer (Fig. 10), grader and sheet counter/stacker. The sheet maker and dryer was 9.7 m long × 1.8 m wide × 1.8 m tall, had a 1.3 million BTU gas burner at each end, seven 0.9-m fans, and could produce 14,000 sheets per hour. It was basically a minipaper making machine. The nori baskets were dumped into a water-filled sorting tank to remove flotsam and jetsam, usually rockweed bladders and other types of seaweed. The slurry was drained into the baskets then dumped into a centrifuge to remove most of the water. Then the fun began. The gross characteristics of the nori were examined by rubbing the nori between my fingers to get a feel for toughness. This would determine how finely the chopper-grinder must work to make a good sheet. The chopper-grinder comes with four removable blades offering 3, 5, 7 or 9 cutting edges. The goal is to chop as finely as possible without clogging the machine; the tougher the nori the less cutting edges can be used, resulting in a coarser, less desirable sheet. There wasn’t much art in determining which cutters to use; if the blades could not cut the nori, the machine would overload and shut off. The next step was to adjust the density of the nori slurry. A photo-electric light was focused through the slurry in the density adjuster and gave an arbitrary number from 50 (less dense) to 200. A more-dense slurry produced a thicker nori sheet. The sheets had to be a certain thickness; too thin and it would have erratic edges and holes, too thick and the sheet was unmarketable. The sheets had to average 3.0 g when dried to be marketable. The density had to be adjusted throughout the drying process, as the characteristics of the nori changed from harvesting. As the process was started, one had to guess what the right density was, as the results wouldn’t be known until the first sheets were made. A wrong guess would result in several hundred unusable sheets (Fig. 11). The slurry was pumped from the density adjuster into the sheet maker/dryer. The slurry was distributed into seven “buckets” the size of a nori sheet. A spongelined pad squeezed the nori in the buckets onto bamboo pads that then moved into the dryer (Fig. 10). There were a number of different sponges used to press the nori, depending on the coarseness and toughness of the nori. If the wrong sponge was used, the nori would stick to it and not fall off the sponge at the end of drying, ruining the sheet. First-of-the-season nori required a different sponge than later-in-the-season nori. The dryer could hold 28,000 nori sheets. The pads are slowly rotated through the dryer at 14,000 pads per hour. Proper drying required 70-80 percent humidity. Less than that and the sheets would become too dry, crispy and crumbly (Fig. 11). As the first sheets entered the dryer, they were almost always useless, as the empty dryer became too hot. Providing outdoor ambient air into the drying room can help if outside conditions are humid, something not uncommon in Eastport, ME. As the machine filled with nori sheets, the dryer became more humid and sheet quality improved. A plastic curtain wall was placed around the machine to confine the space around the machine, helping to increase the humidity. As the drying process continued, constant attention was required at the density adjuster to provide the best slurry entering the dryer, and at the buckets where the nori was stamped out. When the buckets overflowed, the excess was pumped back into the density adjuster to reduce the waste. When the nori was not chopped finely enough, the sheets produced were too coarse, stuck to the sponges, and would not release from the bamboo pads. To add to the challenge, the dryer had many moving parts and frequent jams. There were a huge number of minor adjustments constantly needing attention to prevent major log jams of bamboo pads. Here is where one had to align one’s spirit with that of the machine, becoming attuned to every little click and clunk, blockage or obstruction that might forewarn of a breakdown. Taking 30 FIGURE 8. Nori harvesting. FIGURE 9. Chopper/grinder.
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