Beer Forum

So I decided to use a pressure cooker and sterilize some nalgene bottles to repitch yeast ala Jamil. My only problem is I don't know the specifics and so I have some questions. 1. Does the bottle need to be completely submerged in water, or will the steam kill everything too. 2. How long do I need to keep it at temperature, 1 min. 15 min? 3. Anyone have any tricks for pulling it out without recontaminating it? I figured I would just be super careful.

Thanks

Drew Beechum's article on yeast starter wort in a pressure cooker
http://www.maltosefalcons.com/tech/startermadeeasy.php


1) Yes the steam will kill everything.
2) 15 mins
3) Let them cool down naturally or you will burn the shit out of yourself.

HTH-

BDawg'S advise is good. As far as getting the thing out without burning the crap out of yourself goes, your pressure cooker should have a wire rack with handles that stick out above the level of whatever you put in there. You simply grab the rack handles and lift.

If you have access to a pressure cooker to sterilize a nalgene bottle, you should really consider canning your starter wort. Beechum's article talks about doing it with DME, but I do a 5 gallon all grain batch at a time. It's much cheaper than using DME. I put it up in quart jars. I only have to make up starter wort 2 - 3 times a year. It's really convenient to just pop open a jar or two, pour into a sanitized flask and pitch the yeast. Less than 5 minutes to get a starter underway. You ought to give it a try if you brew very often at all.

Wayne
Bugeater Brewing Company

I brew everyweekend, and bug I have to say that is the best advice that I have got so far. I never thought of doing that!

I bought my Pressure cooker at KOHLS about 2 months ago. I did exactly what Bug is talking about except I used DME. A good days worth of prep time but when I need a starter. Wham! there it is . I need to do the AG method to save some cash down the road. Did you add hops? I wouldnt think so.
For boil time I brought to boil untill the steam escapes then put the capper thing on and adjust heat so it rocks back and fourth. Let go for 15 min . turn heat off and let cool slowly. Too fast and it will suck in air and possible bugs. At least thats how I did it.

boise_brewer wrote:So I decided to use a pressure cooker and sterilize some nalgene bottles to repitch yeast ala Jamil. My only problem is I don't know the specifics and so I have some questions. 1. Does the bottle need to be completely submerged in water, or will the steam kill everything too. 2. How long do I need to keep it at temperature, 1 min. 15 min? 3. Anyone have any tricks for pulling it out without recontaminating it? I figured I would just be super careful.

Thanks

I would suggest checking out the book for your pressure cooker. The point of the pressure cooker is to have whatever you are trying to sterilize IN the steam. Be careful not overfill it with water.

I started canning wort thanks to Drew Beechum's tech and tips on the Maltose Falcons site. I love it. 15 minutes seems to be fine for the wort as I haven't had any lids pop. That seems to be good enough evidence that things are sterile.

I can pints because my pressure cooker isn't big enough for quarts. I use extra canning rings to keep the jars off the bottom (I imagine the same would work for plastic). I follow Drew's procedure with some adjustments made for my own pressure cooker. Mine has a weight (regulator) that can be held up to vent the steam or turned a bit to hold preesure. I let it vent for 5 minutes to make sure that the vessel is filled with steam and then close it. I start my 15 minute timer when steam again starts coming through the regulator. I also adjust the flame as low as I can get it with steam still escaping. I let it come down to temperature on it's own. The inside of the vessel will be sterile until it is exposed to outside air. My cooker has a vent on one side that opens when there is no pressure in the vessel, so it doesn't remain sealed, but I don't let that make me too paranoid.

I have been trying to decide whether the break that is in the jars is good for the starter or bad for the beer. I have just been swirling it all up and putting it in my starter, usually a half gallon growler. I pitch my whole starter in the wort since it usually has just been going for a few hours. A little break is good for the yeast, right? Nutrients and all that?

Cheers,
Chad

Steam is the key to sanitizing/autoclaving with a pressure cooker. Some people might not understand this so I'll just throw in a quick explanation.

In order for water to change phase from liquid to steam, it has to absorb a huge amount of heat. It doesn't get any hotter but it carries much more energy. Something like 540 cal/g I think. Anyhow, anybody who has been burned with steam knows that a little steam will burn the holy piss out of you. NOW, if you increase the pressure, the water must absorb even more heat to become vapor so it is now carrying WAY more energy and would love to transfer that energy to microbes living in your nalgene bottles and cook em up. That's why some medical instruments are steam sterilized and not boiled. The steam just carries more heat energy than the liquid.

There are also a couple ways to bring down the temp on a pressure cooker. Some have a steam release valve and that's kind of a newer thing. The older cookers with the jiggle top can be dumped into a cold water bath if need be.

As a side note, I melted a plastic container in a pressure cooker by letting it touch the bottom while on the flame.

Just enough water to cover the bottom plate. 20 minutes at 15PSI is the standard autoclaving practice (pressure cooker/autoclave - same thing). Turn down the heat when it gets to 15PSI, and keep adjusting it to keep it there. Yes, the weight is supposed to keep the PSI at 15PSI, but you can NEVER be too careful around a pressure cooker. I've seen mine get close to 18PSI if I keep the fire all the way up.

Let it chill down naturally. If your pressure cooker doesn't have automatic interlocks that keep it from being opened under pressure, toss it and buy a new one. A modern pressure cooker in good working condition is almost foolproof. Older ones without the safety features of modern ones can be extremely dangerous.

On mine, the interlocks won't let me open it up while there is any pressure remaining. Once it lets me open it up, I usually do so to cap the bottles tightly. Standard canning practices apply, never tighten the caps on anything in a pressure cooker. Canning jars are put in with caps loose, and the lids vacuum seal as they cool down.

walmart dot com sells a pressure canner that isn't available in stores as near as I can tell. It takes quart jars, erlenmeyer flasks, test tubes, and anything else.

I'm a sterilization freak, I pressure cook all my starters, and slants prior to use.