OSLO the Indestructible

As Lab Manager at Bootleg Biology, it’s my job to baby our cultures as we grow them from a few cells to larger pitch sizes.

Since we first started performing tests on OSLO, or isolate 130A as we first knew it, we’ve been trying to make a bad beer with it. It just didn’t seem to cooperate.  Couple that with hearing some pretty amazing performance feedback from our friends and customers who were using OSLO, and you start to get the impression it’s impossible to make this yeast perform poorly.

And that’s why I decided to REALLY put this culture through the ultimate viability test.


Be so delinquent in handling of OSLO that not only will it make bad beer, but also shouldn’t make beer at all.


Back in May we took a fresh homebrew pack of OSLO and left it unrefrigerated in the warehouse part of our facility for 18 days. The pack swelled up in the warehouse as the temperature held steady at around 80F/26C. Gotta love Tennessee’s version of “Spring.”

After 18 days we pulled together a small, half-gallon test beer using DME and cascade hops. The OG was 1.043, and to add even a further stressor, we pitched at a higher temperature than we had ever tested OSLO before — 99F/37C! For the half gallon batch we pitched at the same pitch rate as our homebrew pack (5ml of the 50ml slurry). 

Surely we had killed OSLO with poor storage and a very high pitching temp?! Well…..

We pitched the test batch at the end of the day on May 28 around 5:30 p.m. When we came into the lab the next day at 10 – yeah, 10 a.m., don’t judge – the jug was chugging along. We had left the jug in our propagation room where it had settled in around 87F/31C. At 24 hours we took the first gravity reading: 1.027. 

After 48 hours, the beer was still around 85F/29C and the gravity was at 1.012.

And finally after 72 hours, the beer was at a terminal gravity of 1.008. 

The finished product? A typical OSLO flavor profile. Clean malt character with the hops bringing a nice splash of grapefruit, and no noticeable off flavors. 


Is OSLO the Terminator of beers? Probably. 

Should OSLO ever be refrigerated? 😂

Ultimately, if there ever was a yeast that didn’t need to be coddled, it’s OSLO.  Now, back to the yeast nursery with all those other babies.

Sam Wineka

Bootleg Biology Lab Manager

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