"Hops take up a lot of real estate," he said.

The seedlings started off small when Cabrera planted them, smaller than a beer bottle. Photo: Mark Cabrera.

The idea started when the manager of the community garden at Lake Merritt approached Cabrera last fall and asked if Bison Brewery was interested in growing in an open plot at Lake Merritt. The garden waived the fee for the brewery. Bison's head brewer did research on the best hops plant for Oakland. They settled on the Cascade Hops, a variety that does well in less warm weather, and Cabrera got to work planting earlier this spring.

First, him and his son planted in the Lake Merritt community garden, but they had rhizomes left over. Rhizomes, seedlings that look like sticks, come in one-size large boxes and "we had about ten times as much as would fit," said Cabrera.

But, right next to his spot in the community garden was another empty spot. He asked about it and found out the spot had just been promised to The Victory Garden Foundation. He reached out to Victory Lee, the founder of the organization, and she offered up space not at Lake Merritt but at the People's Victory Garden, where the festival will take place. That used up some more of the seedlings, but not all.

"We ended up planting all over," said Cabrera -- his own house, two home-brewing friends' houses, Beer Revolution and Olde Depot.

The little seedlings grew, turning into vines over the summer. At Cabrera's house, they wrapped up the lattice-work and onto his 25-foot roof.

When it came time to harvest the flowers, though, Cabrera didn't expect much. "Maybe one keg," he said. Growing your own hops can be a notoriously time-consuming process. It typically takes two to three years for the hops to really take root. After harvesting, you trim the vine down to a few feet, let it hibernate over the winter, and it blooms again in the spring bigger and better.

Cabrera poses next to the vines that grew nearly 40-feet-high this summer. Photo: Mark Cabrera

Cabrera was pleasantly surprised, though, when they ended up with 30 pounds of hops, which turned into 40 kegs of Oakland Hops Harvest -- a West Coast-style pale ale.

That special beer is or will be in the coming weeks available at Olde Depot, Saturn, Jupiter, The New Parkway Theater, Ben & Nick's, Commonwealth and other bars in Oakland and Berkeley. Or, you can drink it for a good cause at the Hops n' Harvest Festival.

The festival, from 1 to 5 p.m. this Saturday at the People's Victory Garden at Telegraph Center, will have classes, workshops, dancing, music, food and, of course, beer.

Next year, Bison intends to harvest the hops again -- and, hopefully, get a bigger bounty. It'll also be looking to do similar urban hops growing in other regions like Santa Rosa and Sacramento. And, the brewery plans to reach out to homebrewers, many of whom wanted to participate or grown their own. In fact, the Hops n' Harvest festival will include a homebrewing demonstration with the Oakland hops.

"I had no idea it was going to be this much fun," said Cabrera.

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Bison Brewery Grows Hops in Oakland, Brews Up Local Beer