The Rare Barrel
 
March 18, 2014 | Sour Beer | The Rare Barrel

Now Serving Draft Beer at 44°F

If you've had the chance to visit our tasting room in the last three weeks, you might have noticed something different about our beer: it's warmer. We are now serving our draft beer at 44°F, which is about 4°F warmer than we were serving our beer for the first two months of being open. Why are we serving our sours at a higher temperature? It tastes better.

We had casually talked about serving our beer at a warmer temperature for a little while, but it wasn’t until we had our Beer Week dinner at Mikkeller Bar SF that we realized we needed to serve our beer at a higher temperature. Throughout our five course beer pairing dinner at Mikkeller Bar SF, we tasted five of our sours that were served between 45-55°F, and decided that we needed to make this happen.

Why couldn’t we serve our beers warmer before? Originally, we were using straight CO2 to push beer through our lines. With our old set up, our serving temperature range was limited to 38-42°F. The closer we'd get to 42°F, the more problems we'd experience with foaming, because the CO2 would come out of solution. We could potentially have increased the CO2 pressure to keep CO2 in solution, but that would have resulted in us unintentionally carbonating our beers more, which we did not want to do.

How do we serve our beers at 44°F now? We needed to do the following four things to serve our beer at 44°F:

  1. Increase the temperature on our cooler to 44°F
  2. Increase the applied pressure on our draft system to keep CO2 in solution (CO2 wants to come out of solution at higher temperatures)
  3. Install flow-regulated faucets to provide more restriction to the draft system and counter act the higher pressure on the draft system.
  4. Push beer though the lines with a blend of CO2 and nitrogen, instead of straight CO2

The last part of the puzzle is crucial to the new set up. We recently installed a nifty Green Air Supply, which extracts nitrogen from the atmosphere, then blends the nitrogen and CO2 in a ratio that is calculated for our system. The ratio of nitrogen and CO2 is specific to our serving temperature, draft line resistance, elevation above sea level, and a few other things. Since nitrogen is an inert gas, and doesn’t dissolve into our beer and “carbonate” the beer like CO2 does, we are able to apply more pressure to the whole system, which allows us to serve beer a few degrees warmer.

Sounds like a whole lot of work just to be serving our beer a few degrees warmer, right? We don’t think so. In our tasting room, the tulip glass is the final “package” of our product. Our sours take a very long time to make, and we take great pride in doing everything we can to maintain quality throughout the entire production process. When we find a better way of doing something, we’re going to adapt and improve our processes.

Next time you visit, feel free to leave the mittens at home and let us know what you think about the new serving temperature. 

Cheers, 

 

Comments

Gavin's Gravatar
 
Gavin
@ Mar 18, 2014 at 1:31 PM
I haven't been to your tasting room (and I live on the other coast) but bravo for taking this step. Flavors are better in warmer beers and if you're proud of the flavor this is the right way to serve it. The N2, CO2 mix system sounds like a clever solution.

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