Several new grass roots start-ups are taking the obsessive approach we've grown to expect from third wave coffee, and artisanal cocktails, and applying it to juice. Yes, juice. Tropicana, consider this a warning: all three of these super fresh spots squeeze locally farmed fruits and vegetables within hours of sipping time. 

1) Sow Pop-up: Hell-bent on bucking the stereotype that juice is just for cleanses, Sow pops up every Saturday and Sunday at Pause Wine Bar, serving up freshly farmed fruits and vegetables in the form of made-to-order juices. At last weekend's launch event, options included a red beet-carrot-orange-apple-ginger and a "citrus flight" of ruby red grapefruit, tangelo and navel orange juices. Bring your own champagne. 

2) Juice To You: This Union Street shop allows customers to order juices a la carte—all of them freshly made daily on a hydraulic press. Sip the "Liver Green" juice the morning after you had one too many margaritas. The "Pineapple Pear Chia" is great for sustained energy before a work-out. The shop also stocks a library of juice and health related books for you to peruse as you drink.

3) Corazon Juicebar: Look for the neon-bright yellow exterior of this new Mission juice bar, serving all-natural, organic juice blends with a Mexican spin. The mother-and-son owned joint also serves raspados (Mexican shaved ice) in flavors like hibiscus and guava and housemade kombucha. Stop by for the grand opening tomorrow from 9 a.m. to 8 p.m. for free samples.