What to do with starsan after keg purge

[day_trippr]

fwiw, I do 10 gallon batches with a pair of carboys connected to a pair of sanitized daisy-chained kegs for gas purging, with the end of the line submerged in a small bucket of water as a bubbler. When fermentation is chugging along the brewery has a lovely hoppy aroma so I assume the kegs end up with some kind of hoppy coating inside. As I've never had an evident infection I assume it's a benign condition...

Cheers!

 

[BasementArtie]

but if it doesn't raise pH and the star san still foams like crazy (surfactant in tact), then it probably doesn't matter.

When fermentation is chugging along the brewery has a lovely hoppy aroma so I assume the kegs end up with some kind of hoppy coating inside. As I've never had an evident infection I assume it's a benign condition...

This is what I hope is true. The pH measures good and foams and it's not cloudy.

And as you say the smell from the bubbler at the end of the kegs is very pleasant. But I've always been concerned with VOCs etc.

However I've never been able to find any definitive information on this.

 

[mashdar]

Supposedly pushing starsan out is more effective in creating a very low O2 environment than just using gas to diffuse/purge the air out.

This would be technically true in an ideal universe (with zero friction, everything is a sphere, all collisions are fully elastic, etc).

In the real world, your fittings and tubing are letting enough O2 in that you'll never approach the ideal.

Further, the difference between 1ppb gas and 0.00ppb gas would be a difference of decimal ppt in the beer, i.e. beyond negligible.

 

[BasementArtie]

This would be technically true in an ideal universe (with zero friction, everything is a sphere, all collisions are fully elastic, etc).

In the real world, your fittings and tubing are letting enough O2 in that you'll never approach the ideal.

Further, the difference between 1ppb gas and 0.00ppb gas would be a difference of decimal ppt in the beer, i.e. beyond negligible.

For me it's the ease of setting the keg up for a closed transfer a week before the transfer.

Also the ability to use fermentation gas and reuse the starsan would be ideal me on a personal level trying to reduce water wastage. I'm nearly at the point on my brewday that all water is either used for brewing or used for cleaning for cleaning the equipment as well.

But if it reduced O2 to negligible levels as well I'm happy

 

[Crafty_Brewer]

This would be technically true in an ideal universe (with zero friction, everything is a sphere, all collisions are fully elastic, etc).

In the real world, your fittings and tubing are letting enough O2 in that you'll never approach the ideal.

Further, the difference between 1ppb gas and 0.00ppb gas would be a difference of decimal ppt in the beer, i.e. beyond negligible.

Oh yea, I acknowledge it’s not going to get to 0. I’m just curious if the non-liquid purge using fermentation gas you describe manages to use such a massive quantity of co2 that it diffuses the O2 to the same level as the liquid purge.

 

[mashdar]

Oh yea, I acknowledge it’s not going to get to 0. I’m just curious if the non-liquid purge using fermentation gas you describe manages to use such a massive quantity of co2 that it diffuses the O2 to the same level as the liquid purge.

Post in thread 'Keg purging with active fermentation'
https://www.homebrewtalk.com/threads/keg-purging-with-active-fermentation.628658/post-8004741

That's a famous thread around here. Doug made a lot of overly conservative estimates and assumptions to arrive at 5ppb O2 (gas! so several more zeros in beer). That's assuming total mixing, i.e. not "pushing" the O2 out.

FWIW if there's 1mL of air in your ball lock QD above the O-ring when you attach your CO2 line, that 1mL will contain ~2000x the O2 in the entire worst-case keg under ideal conditions*.

*but as I said above, if we start considering permiability of various tubing, gaskets, and fittings, we're nowhere near ideal.

 

[Crafty_Brewer]

Post in thread 'Keg purging with active fermentation'
https://www.homebrewtalk.com/threads/keg-purging-with-active-fermentation.628658/post-8004741

That's a famous thread around here. Doug made a lot of overly conservative estimates and assumptions to arrive at 5ppb O2 (gas! so several more zeros in beer). That's assuming total mixing, i.e. not "pushing" the O2 out.

FWIW if there's 1mL of air in your ball lock QD above the O-ring when you attach your CO2 line, that 1mL will contain ~2000x the O2 in the entire worst-case keg under ideal conditions*.

*but as I said above, if we start considering permiability of various tubing, gaskets, and fittings, we're nowhere near ideal.

That’s pretty interesting. If I ever get more kegs than what I need to keep my keezer full I might have to try it out. I rarely have an empty keg when I start a batch in primary. Usually one kicks when I’m about ready to package.