2013 had more than a few stories about skyrocketing rents and the potential exodus of the creative class, but yesterday's Christmas edition of the Chronicle exposed another group that can no longer afford to live in the city, even while their industry appears to be booming.

To be clear: we're not talking about the chefs who make up the core of San Francisco's culinary rockstar culture, but rather the skilled folks who make up the prep, line cook and sous chef positions in many of your favorite restaurant kitchen. Despite all the high-profile restaurant openings and countless food blog posts this year, San Francisco's cooking class, as we'll call them, apparently can't make enough to sustain themselves in town.

Here's the Chronicle's Paolo Lucchesi:

San Francisco has the most restaurants per capita of any city in the country, yet according to a 2012 U.S. Bureau of Labor Statistics report, restaurant cooks in San Francisco make an average annual salary of $27,660, well below the average San Francisco salary of $62,680. This year, The Chronicle reported that the median monthly rent for San Francisco apartments listed on one website was $3,398, up 21 percent from 2012.

It's a dynamic that becomes even more troubling given that independent restaurants do not pay cooks very well, due in large part to their traditionally slim profit margins. The 2013-14 operations report by the National Restaurant Association showed that the median profit margin for restaurants with average checks of $25 and higher was a mere 4.5 percent.

So where are cooks going if the local economy won't pay them well enough to cook here? Portland, naturally, among other lesser foodie destinations like Nashville and Charleston. "There are too many people moving to Portland to be cooks," Napa native/owner of LePigeon in Portland Gabriel Rucker tells the Chronicle. The market in PDX, "is flooded."

Those that don't skip town, on the other hand, still have a few options to string together paychecks. On-site cafeterias at tech companies are an increasingly big draw for young talent, who apparently don't have the same patience for the old journeyman career path of line cook to sous chef to head chef. The techies, as they hate to be called, make up a big part of the fine dining customer base says Incanto chef Chris Cosentino, "but they're also the ones with gigantic cafeterias full of restaurants. We cannot compete with their wages or hours."

Anyhow, the truly enterprising cooks are still breaking out on their own and riding the pop-up and/or food truck trends — which some might say is another symptom of young cooks looking for fame and personal branding instead of working their way up the ranks at Perbacco or wherever. Until the city or the industry figures out a better way to compensate cooks who don't always see much of the tip pool, we could be looking at rising prices at the fine dining establishments, or fewer cooks working in more casual restaurants.