Results of my first in-bottle pasteurization experiment!

**PintOfBitter** · 05-27-2009, 01:12 AM

BANG!!!!!

I will be cooking up another batch of ginger ale, and this time I really want to be able to ship some bottles off to my mom, who is a ginger freak. I've been wanting to experiment with pasteurizing already carbed bottles at home, but have found no info about it.

You see what the result was, but let me explain the experiment:

I knew the main concern would be the increase in CO2 pressure at elevated temperatures, so I filled a New Belgium bottle with club soda (very fizzy, as you know) and capped it off. I put the bottle in my pressure canner with 1 gallon of water, and started increasing the temp, rather gently, to a simmer. Pasteurization temp should be able to be kept below 180F I think (can't find good tables that aren't for milk), but I was going for a worst case experiment.

I removed the emergency relief valve (rubber plug) from the canner lid so that it was not generating pressure and high temps.

Anyway, about 5 minutes into the simmer, BANG!!! I now know that I'll be looking at low temp pasteurization!

Question: Anyone have a good idea of how the big guys do it? I know it involves hot water spraying of the bottles, but I don't have any temperature information.

Seen any pasteurization time and temp tables used for beer or soda?

scopey · 05-27-2009, 01:33 AM

Quote:

Originally Posted by PintOfBitter

[...]so I filled a New Belgium bottle with club soda (very fizzy, as you know) and capped it off. I put the bottle in my pressure canner with 1 gallon of water, and started increasing the temp, rather gently, to a simmer. Pasteurization temp should be able to be kept below 180F I think (can't find good tables that aren't for milk), but I was going for a worst case experiment.

I removed the emergency relief valve (rubber plug) from the canner lid so that it was not generating pressure and high temps.[...]

Awesome!!

Especially that part about removing the emergency relief valve...err...but no, seriously, this sounds dangerous. I'm no authority, but my guess is that in the commercial world pasteurization has nothing to do with glass bottles. Maybe try pasteurizing before fermentation and bottling? What do I know, I like to freeze my beer bottles to clear up the beer...

Bokonon · 05-27-2009, 01:36 AM

I looked through "Brewing, Science, and Practice" where I remembered reading about some pasteurization info.

Here's some quick info:
at 53C minimum time to kill population 56 min
at 60C minimum time to kill population 5.6 min
at 67c minimum time to kill population .56 min

The tunnel pasteurizers have a few zones. They first warm up the bottles, then kick it up to pastuerization temp, then cool them down

It also talks a bit about percentage of co2 in the bottle and percentage of head space, but it doesn't give an exact formula.

Bokonon · 05-27-2009, 01:37 AM

Quote:

Originally Posted by scopey

Awesome!!

Especially that part about removing the emergency relief valve...err...but no, seriously, this sounds dangerous. I'm no authority, but my guess is that in the commercial world pasteurization has nothing to do with glass bottles. Maybe try pasteurizing before fermentation and bottling? What do I know, I like to freeze my beer bottles to clear up the beer...

I took it as the emergency relief valve was removed so it would constantly vent and not build up pressure. Which is the opposite of dangerous

scopey · 05-27-2009, 01:50 AM

Quote:

Originally Posted by Bokonon

I took it as the emergency relief valve was removed so it would constantly vent and not build up pressure. Which is the opposite of dangerous

Oh yeah, duh on me

**PintOfBitter** · 05-27-2009, 02:38 PM

Quote:

Originally Posted by Bokonon

I looked through "Brewing, Science, and Practice" where I remembered reading about some pasteurization info.

Here's some quick info:
at 53C minimum time to kill population 56 min
at 60C minimum time to kill population 5.6 min
at 67c minimum time to kill population .56 min

The tunnel pasteurizers have a few zones. They first warm up the bottles, then kick it up to pastuerization temp, then cool them down

It also talks a bit about percentage of co2 in the bottle and percentage of head space, but it doesn't give an exact formula.

Thanks, this is very helpful. I may need to pick up that book sometime.

Yes, I removed the relief valve for safety purposes. The only reason I used the pressure canner was because it is bomb-proof, and would contain the glass. Good thing. One shard of glass blew out the hole where the relief valve used to be, along with a little shot of boiling water. Overall, a lot safer than it could have been, though.

I'll give it another shot with the temps you describe. Thanks again!

**GreenwoodRover** · 05-27-2009, 02:47 PM

I've never used this type of quipment before so maybe I'm off base here, but it's the temp that kills the badies, so why not keep the canner vessel pressurized. Would that provide a sort of quasi equilibrium (the pressure in the vessel reoghly equivalent to the pressure in the bottle) and prevent the bottle from rupturing?
Obvouisly you'd have to cool it back to room temp before releasing the pressure or else "boom" again.

**PintOfBitter** · 05-27-2009, 02:56 PM

I understand your line of reasoning, but I think that the increase in pressure in the bottles due to CO2 expansion would far outweigh the increase in pressure in the canner due to heating. Not sure, but that was my assumption. I didn't have any good info for the solubility of CO2 at different temps.

Bokonon · 05-27-2009, 03:14 PM

Quote:

Originally Posted by PintOfBitter

Yes, I removed the relief valve for safety purposes. The only reason I used the pressure canner was because it is bomb-proof, and would contain the glass. Good thing. One shard of glass blew out the hole where the relief valve used to be, along with a little shot of boiling water. Overall, a lot safer than it could have been, though.

I'll give it another shot with the temps you describe. Thanks again!

I think the pressure canner is a great tool for this since it is really strong. The only thing that it makes difficult is the lack of way to monitor temperature.

You might be better off without using the lid, putting a lot of water in there so the temp changes are slow, stick a temp probe in the water. You would have to come up with some way to cover the vessel but still let out pressure/steam.

Then you could ramp it up really slowly to see how much pressure it can take.

Most glass bottles aren't really designed for high pressure, but clearly they still get pasteurized by the big guys so somehow they do it.

**PintOfBitter** · 05-27-2009, 04:55 PM

i've got another experiment in the works today, and will be controlling the temperature of the bottles. stay tuned for results. i can't see how this will fail using Bokonon's numbers, unless my CO2 volume or headspace is way off. again using carbed H2O for simplicity.

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Hot Glue bottle wax experiment	conpewter	Bottling/Kegging	15	09-08-2009 11:04 PM
Bottle conditioning experiment	kendrid	Beginners Beer Brewing Forum	18	01-29-2009 09:46 PM
Label Removal Experiment Results	drbell	Label Display & Discussion	11	02-18-2008 04:18 PM
Aeration experiment results	brewt00l	General Techniques	2	10-31-2007 08:23 AM
Dishwasher pasteurization experiment update	Finn	Cider Forum	0	08-08-2007 07:16 PM