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Fullcourt
07-20-2017, 05:11 PM
Good Beer Hunting (GBH) just published an article about Societe Brewing in San Diego.
http://goodbeerhunting.com/blog/2017/6/6/you-think-its-crowded-now-societe-brewing-company-in-san-diego-ca
Good, informative article about the two founders.

I haven't brewed for a few years, but I am confused here.
I have read this portion of the article a few times, and I don't understand what the author says they are doing with the hot liquor filling the brite tank before transferring in beer.
After they fill the brite with hot liquor, then send it back to the hot liquor tank, doesn't the brite refill with air and oxygen?

This is about 3/4 through the article. Search for "120".
One of those investments is a 120-BBL hot liquor tank, which they use for the sole purpose of purging their brite tank. Typically, breweries purge their brites with carbon dioxide before transferring into them from fermenters or barrels. Before transferring the fermented beer, Societe fills their brite tanks with hot liquor until they overflow and then pushes it back into the hot liquor tank, ensuring the brite tank is air (and oxygen) free. This allows the brewery to both save carbon dioxide and achieve low-single-digit parts per billion levels of dissolved oxygen (DO).

Installed, this hot liquor tank was a $90,000 project—for that single purpose. Since DO is the single greatest factor affecting the freshness of a beer, this upgrade to a seemingly small part of their packaging process ensures Societe’s beers maintain as low as possible DO levels, and the end result is a fresher product.

BemidjiBrewing
07-20-2017, 05:27 PM
The article doesn't exactly make it clear. But what they are doing is more common on a smaller scale, not so sure on the 120bbl scale. Basically, filling the BBT with sterile, mostly de-aerated water and then pushing it out with CO2 ensures that the tank is completely full of CO2 with only a single tank volume of gas used. Ideally, this leaves a sanitized (close to sterile) tank that has less oxygen present than just running CO2 in the bottom of the tank and purging out the top arm. Simply purging an empty tank from the bottom (how most brewers do it) actually is vastly diluting the oxygen but not completely removing it. It also uses much more CO2 to achieve this lower presence of oxygen.

We (like a lot of small brewers) don't pump our beers between tanks, only push with CO2 in an effort to reduce oxidation and move the beer more gently. Their is just another step forward in trying to keep hoppy beers free of O2.

I'd be interested to hear from other brewers if I missed any big points to their process!

Cheers,
Tom

dick murton
07-21-2017, 01:26 PM
I think you have hit the nail on the head re deoxygenating. The only comment I would add is that IMO they are wasting a hell of a lot of energy and preparation time, by heating up water. Unless you then pass the water through a stripping column to flash off the oxygen (e.g. Alfa Laval's vacuum stripping systems), or boil the water thoroughly with free evaporation for a while, then there is still going to be dissolved oxygen in the hot water - which to my mind is them more likely to flash off in the BBT - so increasing the oxygen content of the CO2!!

Cold tap water, air saturated does just as good a job in my experience as using cold deaerated liquor to flood the tank first. So little oxygen comes out of solution from the cold water into the inert gas (CO2) that it is not worth the expense of deaerating the liquor, especially if you have a limitation on DAW production.

BemidjiBrewing
07-23-2017, 11:51 AM
I agree, Dick - that is a lot of energy use while still ending up with a tank that isn't fully free of oxygen! I am curious if there is any available research that has compared the dissolved oxygen levels of a CO2-purged tank vs a water filled/evacuated bright tank when it comes to unfiltered beer? It would be interesting to see the pre-fill oxygen levels, the DO levels of the beer entering the tank, and the DO levels of the beer prior to packaging. Assuming that the tank is being filled with unfiltered, unpasteurized, cold beer is the yeast still able to reduce the relatively small amount of oxygen present?

Cheers,
Tom

dick murton
07-23-2017, 12:47 PM
The problems with gas purging without water fill are numerous, as plenty of people have commented in other similar discussions.

For what it is worth, when filling large conical MVs, filled with air not CO2 or nitrogen at a flow rate to just achieve turbulent flow, i.e. a clean interface between the purge water and beer, e.g. 400 hl / hr in 4" pipework, the fountain lasted about 2 seconds as a visible fountain, then a slight rise in the beer surface for another 10 to 20 seconds, then flat as a millpond. The oxygen pickup was undetectable

I specified small cones at the bottom of dishes on some new 1000 hl dish bottom BBTs because conventional dish bottoms gas a fountain for well over 30 seconds. The effect was to kill the fountain as described above. Even when we didn't purge thoroughly with water filling after caustic cleaning, the oxygen pick up was only a few PPB.

Fullcourt
07-28-2017, 05:06 PM
Thanks for the replies, folks. I have a better understanding of what is going on. I also would like to see the research that justifies this procedure.

Fullcourt
07-28-2017, 05:11 PM
Thanks for the replies, folks. I have a better understanding of what is going on. I also would like to see the research that justifies this procedure.