Long before you take that first sip of an ice-cold beer, the ingredients that went into that beverage had to ferment for weeks. Now University of Washington chemist Alshakim Nelson is hoping a 3-D printer can speed things along.
Nelson, along with UW researchers Abhijit Saha, Trevor Johnston and Ryan Shafranek, produced a hydrogel as thick as peanut butter that’s composed mostly of water, but also contains a yeast-infused polymer that makes up 30 percent of the mixture.
The traditional way of making beer involves adding yeast cells to a stew of barley, water and other ingredients, then letting them munch on the glucose and turn it into ethanol. After the sugar runs out, the yeast is left to die or remain dormant and sink to the bottom. It’s a sad tale for the yeast, and a messy situation for brewers who have to filter it out.
This technology hasn’t changed much over the past hundred years, but Nelson and his team wanted to find a way to streamline the process and make it easier for brewers.
“By embedding the yeast inside a hydrogel, it simplifies the step of having to take the yeast away,” he told GeekWire.
After the cubes are 3-D-printed, which only takes about five minutes, they are hardened in an ultraviolet light chamber.
The hydrogel doesn’t become as hard as plastic.
“It becomes like Jell-O. It’s jiggly and soft,” Nelson says. “Imagine a cube of Jell-O in a lattice pattern.” The lattice pattern is built up from strips of hydrogel, like Lincoln Logs, to expose the most surface area.
Nelson and his team are about to publish their results in a scientific journal, but their investigation of 3-D-printed hydrogel is far from over.
For starters, the yeast-infused bioreactors seem to be gifts that keep on giving, and fermenting. “They’re able to do it for months and months on end,” Nelson said. “They’re happy workers inside our hydrogels.”
Nelson isn’t sure how long the bioreactor cubes can keep the fermentation process going, but it has been producing ethanol for four months now. Nelson suspects that because the yeast cells are immobilized, their growth and reproduction is stunted without affecting their ability to keep working.
Another thing the team hasn’t tested yet is how the bioreactors might affect the beer’s taste. “No one has been brave enough to do that yet,” Nelson said with a laugh.
Nelson said the team’s continuous-fermentation device is incredibly flexible. Even though the current model has a volume of one cubic centimeter, the hydrogel can really take any shape and be scaled up. With the right type of modification, the method could be used to produce proteins for pharmaceuticals and other biotech products – which would be an achievement well worth toasting.
Hat tip to The Economist.
