The Rare Barrel
March 2, 2016 | The Rare Barrel

Barrel Samples: sensory, attenuation, temperature, and pH

There are many different variables throughout the fermentation process that affect how sour beer is produced. In order to better understand our beers and sour beer production in general, we pull small samples from each batch of beer every 10-14 days and specifically track four things: sensory, attenuation, temperature, and pH.

Pulling Nails

In order to test each batch, we pull a very small sample of beer from the barrel. However, it is incredibly important that we do not allow extra oxygen in the barrel, so we never remove the bungs from the barrel during this process. Instead, we are able to get samples from our barrels by “pulling nails” (often referred to as the “Vinnie Nail”, popularized by Vinnie at Russian River). It’s as simple as it sounds… we grab a pair of pliers and a glass, pull the nail, catch the sour beer as it pours out of the barrel, and then put the nail back in the hole! While sampling is important for testing the beer, it is important not to remove too much beer from the barrel at one time as that could also cause too much oxygen to enter the barrel.


After samples are pulled, our production team first tests the beer on sensory. With over 900 barrels filled, we are sampling sour beer every day. Sight, smell, taste, and mouthfeel of each sample are recorded to assist us in tracking the progress of our different yeast and bacteria experimentations as well as help create exciting new blends. We’ll take notes on how each batch looks, smells, and tastes every 10-14 days so that we can track how it changes over time and know when it has completed fermentation.


Are there still fermentable sugars in the sour beers? Are the yeast and bacteria still fermenting the beer? To answer these questions our production team uses an Anton Paar to measure attenuation and monitor the progression of the fermentation process. The data collected from these readings, show us how much sugar has been converted into alcohol and carbon dioxide over time. If we see weeks of stable readings, we know that yeast and bacteria have fully attenuated the beer and that this batch of beer is either ready to be packaged or blended. Ensuring that our beers have fully attenuated and are fermented dry is very important to make sure that our beers do not over-carbonate in the bottle.


Temperature plays a very important part in yeast and bacteria activity. Yeast and bacteria typically convert more sugar into alcohol and carbon dioxide in hotter temperatures, while fermentation can slow down in colder temperatures. Since the amount of heat present affects how yeast and bacteria act, it also affects how sour beer tastes and smells. Different fermentation temperatures will produce different esters and phenols, which give each batch of beer varying characteristics. The ideal temperature range is somewhere between 50-70F, which is actually one of the main reasons why we decided to start here in Berkeley. Berkeley’s climate hovers in the ideal fermentation temperature range. The size and location of our warehouse provide an excellent space to house our 100 BBL fermentors and over 900 barrels filled with fermenting beer.


The final assessment that we record every 10-14 days is pH level. pH is the measure of how acidic or alkaline a solution is. Bacteria produce acids (most commonly lactic and/or acetic acid), which acidifies our beers and puts the “sour” in them. We track the progress of acid producing bacteria by taking a pH reading. Bacteria are still active if pH continues to decrease, but after consecutive weeks of stable readings we are able to proceed in the blending process.

How do we test pH? First, we calibrate a probe to 7.0 pH by dipping it into a neutral storage solution. We then rinse the probe with water and dip it into the second acidic storage solution to calibrate the probe to 4.0 pH. We rinse the probe one more time with water and then dip it into our beer sample to take a final pH reading.

pH will give us a good idea of how acidic a beer is, however, it doesn’t directly translate to how people perceive acidity on their pallet.

Recording the data from these four assessments allows us to further our understanding of how yeast and bacteria work to create sour beer. We learn more and more as we track each batch of beer in this decades long experiment.


Time Posted: Mar 2, 2016 at 9:00 AM
The Rare Barrel
September 21, 2015 | The Rare Barrel

The Sour Hour Podcast

Do you like learning about sour beer? If so, you might enjoy The Sour Hour podcast on The Brewing Network!

The Sour Hour is a podcast made for sour heads, homebrewers, and professional brewers who are interested in spreading knowledge sour beers.  The show is hosted by Scott Moskowitz of The Brewing Network and Jay Goodwin from The Rare Barrel, and they are usually joined by special guests on each episode.

The Sour Hour is available for free through iTunes! If you have any questions you’d like Jay and Scott to answer on the show, feel free to email your questions to or call 888.401.BEER when they are in the studio!

Here is a list of episodes and special guests that are available at the time of this blog post…

Episode 1 – Michael Tonsmeire, author of American Sour Beers

Episode 2 – Lauren Salazar of New Belgium

Episode 3 – Cory King of Side Project and Perennial Artisan Ales

Episode 4 – Troy Casey of Casey Brewing and Blending

Episode 5 – Tim Clifford of Sante Adairius Rustic Ales

Episode 6 – Q&A Episode

Episode 7 – Nick Impellitteri of The Yeast Bay

Episode 8 – Chad Yakobson of Crooked Stave Artisan Beer Project

Episode 9 - Q&A Episode

Episode 10 – Rudi Ghequire of Rodenbach Brewery

Episode 11 – Jean of Cantillon, Vinnie of Russian River, and Rob and Jason of Allagash

Episode 12 – Jim Crooks of Firestone Walker Barrelworks

Episode 13 – Milk The Funk

Episode 14 – Adrienne Ballou and Garrett Crowell of Jester King Brewery

Episode 15 –Jester King continued 

The Rare Barrel
September 3, 2015 | The Rare Barrel

Err On The Side of Awesome - A Collaboration with New Belgium


a wise man advised
"you should err
on the side
of caution"

to that they replied
"we will err
on the side
of awesome"


The Story

Last week was awesome. Jay and Alex flew out to New Belgium Brewing to blend a sour beer with Lauren Salazar. Our friend Lauren is the Blender at New Belgium, a giant in the world of sour beer, and an all-around badass. The final blend we created is called “Err On The Side Of Awesome”, but in order to fully understand this collaboration, we’re going to take a step back in time…

On a brisk afternoon in the fall of 2007, Alex’s uncle took him on a tour of New Belgium. While Alex was on the tour, he realized that brewing is using the science of biology to create art… to create beer that was way better than the stuff he was drinking at the time (crazy as it is, Alex's mom caught a picture of that exact moment below). Upon returning home, Alex got a homebrew kit, and started brewing in his kitchen with his roommate and best friend, Jay. Fast forward in time, Jay is working at The Bruery, Lauren teaches him how to start their sensory program, and a friendship is born.

Roughly around the same time that Alex went on his tour of New Belgium though, New Belgium was looking to get rid of a few of their oak barrels, and decided to send them out to other breweries. Lauren marked the barrels that she wanted to keep and she marked the ones she wants to send out. Time passes, the seasons change, and she finds herself visiting Russian River. While she’s touring Russian River, she sees a barrel marked “pH1”… which was never supposed to leave New Belgium! pH1 was one of New Belgium’s original seven oak barrels and it was producing amazing sours. Whoops. This barrel, pH1, ended up contributing to Russian River’s exceptional beer, Beatification, and ended up living there for quite some time.

A few years later, Alex and Jay catch wind of this story, and love the idea behind it… the idea that there is this one exceptional barrel that has a perfect blend of yeast and bacteria. With that in mind, Jay and Alex decide to name their brewery “The Rare Barrel”, in reference to the legendary pH1.


About one year ago, Russian River surprised Lauren by sending her beloved pH1 back to her! She excitedly filled it up, and began to age a cherry sour in it. The cherry sour aged for a year, and brings us back to present time. pH1 has bright cherry notes, is assertively sour, and very dry. pH1 is bold, and pH1 is ready to be blended. By this point, we’re good friends with Lauren, and a collaboration with New Belgium and The Rare Barrel is born, with pH1 right smack dab in the middle of it.  The circle is complete.

The Collaboration

Lauren, Jay, and Alex spent three epic days in the wood cellar tasting through a wide variety of samples from New Belgium’s barrel and foeder program. We started with pH1 at the center, which was assertively sour and dry with bold cherry notes and free from off flavors. It was a perfect beer to blend with, because it had so much personality that we were able to carry though the entire blend. After days of tasting, blending, tasting, and more blending, we came up with a blend that we were all quite proud of.

The final blend consists of pH1, eight oak barrels of cherry sour, and parts of 2 foeders of Felix (pale sour). Check out the video below for a fast tour through the wood cellar to see pH1 and the 2 foeders. The final blend ratio of Err On The Side Of Awesome is 4 parts cherry sour, 1 part Felix from Foeder 59, and 1 part Felix from Foeder 29. Err On The Side of Awesome is assertively sour with bright notes of cherries, pineapple, white wine, and friendship. 

For more details on this collab, feel free to check out The Full Pint's story too. 



The Rare Barrel
September 2, 2015 | The Rare Barrel

2016 Ambassadors of Sour Details


UPADATE - 2016 Ambassadors of Sour is now full and enrollment has closed. 


We are excited to announce that we are opening enrollment for Ambassadors of Sour, our 2016 beer club! Enrollment opens to new members on Thursday, October 1st at 9am. Click here to learn more about the benefits of being an Ambassador!

The Rare Barrel
October 7, 2014 | The Rare Barrel

Awarded Gold Medal at the 2014 Great American Beer Festival®

The Great American Beer Festival (GABF) is spectacular event that combines both beer tasting and a competition. On the competition side of things, GABF happens to be the largest commercial beer competition in the world. We we're excited just to have the opportunity to pour our beer at the festival, but thrilled when we found out that we won an award!

Photo © 2014 Jason E. Kaplan


This year, Cosmic Dust was awarded a Gold Medal for American-Style Sour Ale (category 22) at the 2014 Great American Beer Festival. As a brewery that focuses entirely on producing American sour beer, we couldn't be more proud to take home this award. 

Cosmic Dust, the sour that was awarded a gold medal, is a golden sour beer aged in oak barrels with hibiscus. The base beer was fermented with Brettanomyces claussenii and Pediococcus damnosus. With a moderate acidity, this sour beer showcases subtle earthy and berry characteristics with a light Brett funk. 

Our bottles of this beer have finished bottle conditioning, and we're excited to release Cosmic Dust as our 4th Founder's Club Exclusive Bottle Release! If you're a Founder, we've already emailed you the details for the release. If you aren't Founder, we'll have Cosmic Dust on draft in the Tasting Room for another week or so!


The Rare Barrel
August 5, 2014 | The Rare Barrel

Echo Series: an experiment with un-rinsed barrels

We like to experiment here at The Rare Barrel, and sometimes those results are not only worth tasting, but also worth writing about. One of these experiments that we have been working on is called the Echo Series.

In short, the Echo Series is an experiment where we let the yeast/bacteria/beer and sometimes fruit from one barrel, influence the fermentation and flavors of the next sour beer to fill up that barrel. In order to fully understand what we are talking about though, we’ll give you a little more back story.  

When one of our sour beers has finished barrel aging and is ready to be packaged, we will transfer most of the sour beer from each barrel into the blending tank.  With the help of a sight glass, we continue to  remove most of the sour beer from each barrel, and stop removing the beer when  we start seeing yeast, bacteria, and sometimes fruit in the sight glass. We then leave the remaining mixture of beer, yeast, bacteria, and fruit in the bottom of the barrel, which is typically about a few inches of liquid in the bottom of the  barrel.. Typically we would rinse the barrels before refilling them, however, with the Echo Series we fill the barrel with another sour beer without rinsing out the previous remnants and let the refermentation process begin. This means that there are still millions of cells of yeast and bacteria  transferred over to the next beer… the same yeast and bacteria that have already proven themselves to create a great tasting beer!

Hypnotized, the first beer to be released in the Echo Series, is a red sour that aged in barrels that were previously used to age Ensorcelled (dark sour beer with raspberries). With Hypnotized, we noticed a few significant differences between that beer and its counterpart that we aged in rinsed barrels. Firstly, we found that Hypnotized finished attenuating faster and had a cleaner character (free from off-flavors normally seen in sour beer making) than the same red sour beer aged in rinsed barrels.  The more advanced yeast and bacteria that did a great job fermenting Ensorcelled seemed to really help give Hypnotized a terrifically balanced acidity while being clean and highly drinkable. Additionally, we noticed that it picked up a very subtle raspberry character from the un-rinsed barrel, which added another layer of complexity to the flavor profile.

Hypnotized (Echo Series) is our first release in this series. Needless to say, we’re pretty excited about our continued experimentation with re-using advanced yeast and bacteria from the oak. We have a few more Echo Series beers in the works, and look forward to sharing them on draft in the near future.



The Rare Barrel
July 29, 2014 | The Rare Barrel

Collaboration Series: On the Shoulders of Giants

Sir Isaac Newton once wrote “If I have seen further, it is by standing on the shoulders of giants." As an all-sour beer company starting out in a thriving craft beer revolution, this quote has struck a chord in our hearts.

Take a moment to think about your favorite craft beer, your most memorable brewery visit, and the friends you’ve met through your shared interest in craft beer. The craft beer revolution that we enjoy today has grown and flourished through the hard work, passion, and dedication of the brewers and pioneers who paved the way for those of us who are starting breweries today. We have the utmost respect for those who have come before us and shaped the amazing craft beer industry that we have today.

In honor of those who have contributed immensely to the growth of craft beer, we are starting our first collaborative series of beers, called “On the Shoulders of Giants”. In this series, we will collaborate with a person (aka a “giant”); someone who has significantly and positively changed the landscape of beer. Once we have blended and released a beer with one of the “giants”, we will work with that person to select the “giant” for the next collaboration in the series.  In our first installment of On the Shoulders of Giants, we collaborated with our personal “giant”, Pete Slosberg.

Pete Slosberg co-founded Pete’s Brewing Company in 1986. His flagship beer, Pete’s Wicked Ale, was an American Brown Ale that was made with an all-malt recipe and a focus on quality ingredients. In a time when craft beer awareness wasn’t nearly as prevalent as it is today, Pete understood that education about craft beer was paramount to understanding awareness about craft beer. In order to promote better understanding about beer, Pete created “Pete’s Landscape of Beers”, an educational tool that he used to “teach anyone to be expert in craft beer in 10 minutes”. When hiring a new employee, the offer letter included three books, and the new hire was required to take a beer test on their first day with the company. In a time when 6 packs were the norm, he was among the first package his beers in a 22 oz. bottle as a core strategy for the packaging (take a moment to think about how much of an impact that has had on how we try beer today!).  And what about cans? Pete was among the first craft breweries to put his craft beer in cans, which eventually could be enjoyed on four different airlines. In a time when seasonal varieties were limited to just a Christmas or pumpkin beers, Pete was the first to offer four different seasonal beers. Pete's Brewing Company was the first to sponsor the Ninkasi Award through American Homebrewers Association, an award given to the most awarded homebrewer at the National Homebrewer's Conference. Part of the prize included being the first homebrewer to do a collaboration that was released nationally. When KQED hosted a beer fest in the early 1990’s and asked Pete for a donation, he auctioned off a dinner with himself, instead of the traditional case of beer or shirt. Greg Koch and Steve Wagner won the auction and joined Pete for dinner, a few years before they went on to found Stone Brewing Company. When Facebook and Twitter weren’t yet an option for communicating with his followers, he created an ad campaign in 1994 that the NY Times said was one of the top 10 nationally, across all companies. When Pete heard he was going to be a first time grandfather, he approached Drie Fonteinen about blending a special sour beer in honor of his grandson's birth, a beer that could be cellared for 20+ years for that generation.  Armand and Lydie thought it was a crazy idea, but supported it.  For the first time ever, Armand blended a beer from only his worts.  This inspired Armand and Lydie to create their own unique offering from this blend, Armand 4, Spring. In a time when the options for craft beer were few and far between, Pete did things his own way. With 10 years of over 100% growth and making the Inc. 500 list for fastest growing private company, Pete’s Brewing Company was a force in craft beer that changed the idea of beer as we know it today.

In our first installment of “On the Shoulders of Giants”, we gave Pete the keys to our barrel house, and let him create his perfect sour. After tasting though countless barrels, Pete decided to create and blend a dark sour beer with sour cherries. Pete chose the barrels, blended the beer, added the sour cherries, bottled the beer, and visited often to check-in on his blend. With rich notes of dark chocolate and cherries, this beer is arguably one of our most sour beers yet. With the recent birth of his granddaughter McKayla, Pete created this beer with the intention of sharing these bottles with McKayla on her 21st birthday, in 2034 (we can’t guarantee this beer will age that long, but will definitely be tracking it’s progress over the years!).

Pete – Thank you for all you have done in craft beer to create an environment where a few guys with the crazy idea of starting an all-sour brewery have a chance to share our passion with the world.  If we have seen further it is by standing on your shoulders. 


Time Posted: Jul 29, 2014 at 1:21 PM
The Rare Barrel
April 14, 2014 | The Rare Barrel

Awarded Gold and Bronze Medals at 2014 World Beer Cup ®

Last month, we entered four of our beers into the 2014 World Beer Cup, a global beer competition that evaluates beers from around the world and occurs once every two years. The competition is steep. This year, 1,403 breweries from 58 countries competed.  219 judges from 31 countries spent three full days judging beers across 94 categories. When all was said and done, of the 253 breweries who won an award, just 27 breweries won more than one award. To our astonishment, we went home with two awards from the 2014 World Beer Cup!

Category 18: American-Style Sour Ale

Award: Gold 

Beer Name: Ensorcelled

Beer Description: Dark sour beer aged in oak barrels w/raspberry


Category 59: Belgian-Style Flanders Oud Bruin or Oud Red Ale

Award: Bronze

Beer Name: Shadows of Their Eyes

Beer Description: Dark sour beer aged in oak barrels

We’d also like to give a big shout out to our friends at The Bruery, who took silver medal for Oude Tart in Category 59! 

Well, that’s enough of us tooting our own horn. The barrels need tending to…


The Rare Barrel
March 12, 2014 | The Rare Barrel

FAQs - Tasting Room, Founder's Club, Bottles, & Growlers


You have questions, and we have answers. Here are a few frequently asked questions that we have some answers for:

Why is the tasting room only open on Friday and Saturday?

We currently don’t have enough draft beer to open up another day. We do intend to open the tasting room on Sunday and potentially Thursday when we have more beer, but until then, we’re going to have to stick with only Friday and Saturday.

Will you expand your seating in the tasting room?

Yes. We are installing an additional 20’ bar top that will seat 20 people. This communal table should be ready for the week of March, 28th.

Why don’t you do samples or sample flights?

You might have noticed that we currently only offer 10 oz pours of our sours, and do not offer sample sizes or flights. Why is that? Well, we believe the 10 oz pour combines the best of both worlds since it is a small enough size for you to try multiple beers without becoming over intoxicated, while at the same time it allows us to maintain timely service. Based on the number of visitors we have and the way our bar set up, we would sacrifice timely service in order to provide you with multiple smaller pours. We’d prefer to get a tulip in your hands in under 5 minutes than four samples in your hands after a 15-20 minute wait. We always have tasting flights in the back of our minds, but until we’re able to do it a manner that doesn’t sacrifice service, we hope that the 10 oz pour is a happy medium!

Where can I find your beer outside of the tasting room?

In order to continue keeping the tasting room open on Friday and Saturday, we’ve paused self-distribution around the Bay Area. For the short term, draft is only available in our tasting room.  

How do I enroll in the Founder’s Club?

Unfortunately, enrollment for the Founder’s Club closed last October. However, if you would like us to email you when the details for our 2015 beer club are ready, simply click here and submit your email address in the form at the top of the page. We’ll drop you an email sometime around fall with the details for the next club!

Do you fill growlers?

We are currently testing out a growler program with our Founder’s Club. Once we have enough beer to fill more growlers, we plan to offer more growlers in the Tasting Room. We don't have enough beer to fill a lot of growlers right now. In order to manage our supply of draft beer, we can only fill our growlers.

Do you have any bottles for sale?

As of today, we do not have any bottles available for sale. However we do have a number of brands that are bottle conditioning and should be ready in the upcoming months. If you would like to know when our bottle releases are, follow us on Facebook, Instagram (@therarebarrel), Twitter (@therarebarrel), and our newsletter.

Do you ship beer?

One of benefits included in the Founder’s Club is that we can ship your bottles of beer directly to your residence or business in California. We do plan on expanding our direct shipping program outside of the Founder’s Club at some point, but are not sure when that will be. 


We hope that answered a number of the questions you may (or may not!) have had. If you have any other questions, feel free to email us at 


The Rare Barrel
June 27, 2013 | The Rare Barrel

Where have we been?

We haven’t updated our blog recently, and we are here to do something about that. We’ve been quite busy around The Rare Barrel lately, and would like to share some recent events with you.

We started brewing in February and it’s kept us very happy. While we started off brewing once every other week, we recently upped it to brewing two times every three weeks. That’s still a relatively small amount compared to most breweries, but with all of the preparation and work involved with sour beer, we stay busy.


More equipment allowed us to increase our production and prepare for packaging. This new equipment includes a second 30BBL fermenter, a 15BBL blending tank, and a 70BBL blending tank. The second fermenter has allowed us to double our production, but we aren’t using it to its full capacity yet. We’re expecting to start packaging sometime in the second half of this year. The 15 BBL blending tank will be used to package draft and small bottle releases, while the 70BBL blending tank will be used for our larger bottle releases. Additionally, our bottling line and labeler are currently being manufactured.

We’re also building a tasting room. Woo!  Back in March, we got zoning approval for the tasting room (thank you to all our friends and neighbors who came to speak in favor of it!). The tasting room should be open around late 2013.

How do you like the new website? Click around if you’d like. With this new website, we’re now able to sell our apparel (hoodies, hats, and shirts) and ship to all 50 states. Eventually, we will even sell and ship beer to residents in California using our new website, too.

We’ll do our best not to go this long without posting again. For the most up-to-date news, be sure to follow us on Facebook. For updates in 140 characters or less, you can follow us on Twitter. And for #artsy photos, follow us on Instagram @therarebarrel.



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