Can crown bottle caps be autoclaved?

[zxcvbob]

The folks on the homebrew forum don't know or won't risk answering.  I figure with the diverse knowledge here, somebody might know or be willing to venture a somewhat-informed guess.

I want to mash a couple of pounds of barley malt to make about 6 liters of yeast starter wort, then pressure can it for use later.  When I want to make a yeast starter, just pop a top and go rather than have to mix it up from expensive dried malt extraact, boil it briefly, and wait for it to cool.

I have way too many brown glass beer bottles, and crown caps are cheaper than canning jar lids.  I thought about autoclaving (pressure cooking) the filled open bottles, then capping them when they cool, but there's a small but real contamination risk there.  What about filling and capping/crimping the bottles, and then autoclaving them?  The caps won't need to hold any pressure but I want them to seal air-tight.  I could also recrimp them if necessary after they cool.

What I don't know about is the plastic liner in the caps.  (if I could find some old cork-lined caps this would work splendidly)  From what I've read, modern caps are lined with Plastisol.  What I suspect will happen is the liner will soften or maybe melt in the canner, but that might just glue the caps on.  I don't think that's a problem.  Any ideas?

[AZRedhawk44]

Mead-maker here.

Crown caps do not retain pressure well.  They'll hold in-bottle carbonation for beer most of the time, but they cannot handle the pressure generated by an in-bottle carbonated champagne, sparkling wine, or mead.  Either wine corks or champagne/mushroom corks with wire retainers are needed for that threshold of pressure.  With an appropriately stout glass vessel.

I think the worst that would happen is your crown caps would burst and fly off.  They shouldn't hold to the threshold that the bottle bursts rather than the cap, but I have heard of people's 12oz beer bottles bursting from the process sometimes.

As for autoclaving or pressure cooking a filled bottle with yeast/wort?  I think you'd kill the starter culture along with any undesired elements.  Raising any wort or starter above 80 degrees or so is generally bad for the yeast you want to ferment.  Hitting pasteurization or higher will kill it just like any other unwanted contaminant.  When I get a mash going from grain, I let it steep in the laudening tun for a good hour or so starting at about 150* and it typically comes back out around 125*.  My tun is a 5 gallon Home Depot water jug that I've put a better spout on that I can throttle nice and low for a slow drain, and a wire mesh hose on that spout's inside connection to filter the grains.

After I go through grain extraction, I boil my hops for the appropriate time and then I have to rapidly cool my mash in order for it to be safe to add my yeast, otherwise it will die just about instantly.  In a target 5 gallon batch, my hopped mash will usually be about 2-3 gallons of very high gravity liquid.  I'll do some calculations for a desired fermentation starting gravity and add 1.5 to 2.5 gallons of either cubed ice or refrigerated water and stir vigorously until the mash temperature hits 80 degrees.  Often times I'll have to give the mash an ice bath in the sink since adding the right amount of water or ice will only bring it to 120* or so, and that's still way too high.

I don't do starters, I just pop a yeast packet into whatever I'm making, so I can't help you with this one other than to say just sanitize your 12oz bottles and caps in sani-clean or similar sanitizer, fill them with your starter, and cap 'em.  Pretty sure they'd be fine.  A jug of sani-clean lasts me 15-20 brews, comes out to less than a buck per batch.

[zxcvbob]

I wasn't clear :)  I haven't pitched the yeast yet.  I'm making the starter wort ahead of time, and I want to sterilize it, then will store in bottles or canning jars until I'm ready to grow up a yeast culture.  I might used it months later.  (I've done this before with mason jars) Pasteurization isn't good enough.

The bottle nor the cap has to hold any pressure for this, it just needs to be sealed.

[AZRedhawk44]

Gotcha.  I've never used starters and was under the impression they were typically stored dormant in a fridge with yeast pitched in them, waiting to be pitched into the target brew.

I still think steam pressure would pop the cap on a sealed 12oz bottle in an autoclave or pressure cooker.

[zxcvbob]

I've been storing saved jars of yeast in my fridge, but I don't brew often enough to keep them going.  I recently threw most of them out because they were over a year old.  Next time I brew with kviek yeast, I will dry some of the lees.  (it's one of the few yeasts where that works) But I won't be using kveik yeast until the weather gets warm again.

I bought some 50ml centrifuge tubes with caps (fat plastic test tubes) and I'm planning to start mixing yeast slurry with glycerin and storing it in the freezer.  It will take up a *lot* less refrigerated storage space that way, and last for a couple of years instead of months, which is more to my brewing schedule.  But I'll need starter wort to revive the frozen yeast and build up enough to pitch.

Ultimately I want to get to where I have 3 or 4 "house yeasts" that I use for everything (probably kviek yeast in the summer, kolsch yeast in the winter, and maybe a lager and a Belgian) and almost never have to buy yeast again.  It's also fun to culture the yeast from unfiltered non-pasteurized commercial beers and brew with that.  Bell's Oberon is a good one for that.  One of the best beers I've ever brewed was a porter using Bell's yeast.  But I lost that yeast culture because I didn't brew with it again soon enough.  (of course I can get it again, but it would be a lot easier if I have a few vial in the freezer for next time)

[zxcvbob]

I mashed 2 pounds of pale ale malt today (cheap stuff but reasonably fresh) in about 6.5 quarts of water, and strained it into assorted 12oz and 500ml bottles. Capped them, and processed in a pressure canner at 12 psi for a half an hour. It took a long time to cool down. When I pulled them out of the canner (still a little bit hot), they all had exactly the same headspace, and it was more space than when they went in (oops) I forgot that the liquid would expand -- at least I think that's what happened. I wiped the bottles down with a hot wet rag, and I crimped the caps again. I can turn the caps with my fingers, but it's not easy. So they are not sealed against pressure but they might be sealed good enough to keep bacteria out. Guess I'll find out. I will use one of them next week, and before I open it I'll turn it upside down to see if it leaks.

If I do this again someday, I will fill the bottles to the *bottom* of the necks, and either sit the caps on top without crimping, or I'll cover the tops with aluminum foil. (maybe do some of each)

[charby]

How about getting some 1 or 1/2 gallon wide mouth ball jars? Or bagging up your wort and freezing it.

[zxcvbob]

How about getting some 1 or 1/2 gallon wide mouth ball jars? Or bagging up your wort and freezing it.

Yep, I could use canning jars.  (pints and a few quarts) Done it before.  I wanted to try this :D   

I've thought about freezing it; that would work too.  But my freezer is full.