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TertiaOculus
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Registered: 04/26/20
Posts: 17
Last seen: 3 years, 6 months
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PF Tek: Jar Prep for Pressure Cooker Questions 1
#26630832 - 04/26/20 09:30 PM (3 years, 8 months ago) |
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Hi all,
Note: Using the PF Tek method for P.Cubes
I recently autoclaved my 2nd batch (x4) of 1/2 pint mason jars ever, So I am a TOTAL noob. So I had some questions arise when doing this.
1- What water level should be used? Note: I have a metal platform to keep the jars off the direct bottom of the pressure cooker, BUT I have heard many differing opinions on water level. Some say, do NOT have the water touch the jars at all, others says water touching is OK but only up to 1/3 of the jar should be submerged, and yet I have heard others say 1/2 the jar can be submerged. So what is optimal?
2- What is the best method to keep water out of the jars? I know you have to pre-puncture the inoc. holes (x4 on top), I have simply been putting 1 layer of tin foil on top of them to keep too much water out. The 1st time I had NO problems, the 2nd time 1/2 the batch had a little too much water in them. I have heard that 1 layer of tinfoil should be OK but didn't work for me the 2nd time. I have heard some put 2 layers and yet other do tinfoil + porous tape (masking or micropore) to cover the inoc. holes. What is the preferred/optimal method?
3- Similar to Q2, Can you leave the tinfoil on top of the Jars until it is time to inoculate or will this not allow the jar to air out enough? I autoclaved both my 1st and 2nd batch late at night, finishing around 12-1am and than waited to inoc, till about 4-6pm the next day (so they sat for about 14-16 hours). I left the Jars sealed in the Pressure Cooker until it came time to inoculate to keep them sterile. However I heard some say that it is better to take the tinfoil off of the jar as soon as they cool (which means I would have to break the seal of the PC and remove it)? What is the truth here?
4- Does it hurt if you pressure cook your jars for more than 90mins (@15psi)? I think I may have gone slightly over with the last batch, maybe about 100-110 minutes as I forgot to initially start a timer. Could this have caused the jars to get more water inside?
5- Lastly, when pressure cooking I wait until my "rocker" is bobbing back and forth moderately, set the temp and start a timer, does this sound correct or could I be cooking the jars too high OR low temp?
Thanks for all the advice in advance!
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Mad Hatter
10/6



Registered: 12/20/18
Posts: 169
Last seen: 1 year, 2 months
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Re: PF Tek: Jar Prep for Pressure Cooker Questions [Re: TertiaOculus]
#26630898 - 04/26/20 10:11 PM (3 years, 8 months ago) |
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I personally like to have the jars completely out of the water. I put jar lids at the bottom and then the metal canning rack on top. Then add water to the level of the rack. Having the water level higher doesn't hurt or really make a difference but with 1/2 pint jars, I would have them all the way out since they're short which could allow water to boil up higher than the jars allowing water in.
I've always done 1 layer of foil without any problems.
After I finish pcing I always wait until the pc/jars completely cool and only open once I'm ready to do my work. As soon as they are completely cool its time to open and inoculate. So you do take the tinfoil off as soon as they cool but you also inoculate at the same time. Also if you have a pc with a rocker air will be sucked in once it cools down so it's not necessarily sterile in it. When you sterilize substrates they are never 100% sterile so its best to inoculate immediately before bacteria endospores or other contaminants can germinate or bounce back.
Over 90 minutes doesn't hurt but excessive pc times for certain things can. For example, grains may start to turn to mush or agar won't solidify properly. 110 minutes isn't too long but a bit excessive for 1/2 pint pf jars.
You want the rocker to bobble 1-4 times per minute.
When getting your pc up to temp start slower. If you ramp up the temperature it will cause the water to boil higher initially and possibly getting into your jars.
Don't worry about temperature just focus on 15psi. At different altitudes that will be a different temp but not something you need to worry about.
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TertiaOculus
Not a Stranger


Registered: 04/26/20
Posts: 17
Last seen: 3 years, 6 months
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Re: PF Tek: Jar Prep for Pressure Cooker Questions [Re: Mad Hatter]
#26630912 - 04/26/20 10:21 PM (3 years, 8 months ago) |
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Thanks, that's some great info!
The only issue with the water level is that my jars are only slightly off of the bottom of the PC, maybe like 1/4 or 1/3 of an inch, if I only put that much water in the PC is that enough?
I have been cooking at night so I generally wait till sometime the next day to inoculate as I am very busy. How long does it generally take for the PC and Jars to cool down? Also is it a problem if I wait 14-16 hours?
Good point about the rocker not making it truly sterile, but it still blocks the hole for air to get into the PC at least partially.
Thanks again!
Edited by TertiaOculus (04/26/20 10:23 PM)
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ModularMind
M.P.F.



Registered: 02/09/10
Posts: 7,902
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Re: PF Tek: Jar Prep for Pressure Cooker Questions [Re: TertiaOculus]
#26630923 - 04/26/20 10:28 PM (3 years, 8 months ago) |
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Put 3or 4 jar bands below the rack. It will raise it.
No problem to leave them in there for a few days if needed and keep foil on until inoculation.
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Mad Hatter
10/6



Registered: 12/20/18
Posts: 169
Last seen: 1 year, 2 months
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Re: PF Tek: Jar Prep for Pressure Cooker Questions [Re: ModularMind]
#26630941 - 04/26/20 10:37 PM (3 years, 8 months ago) |
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agreed I normally wait 24 hours after I shut off the pc. makes it easier to plan for work the next day. Waiting longer isn't a death sentence just not considered optimal.
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TertiaOculus
Not a Stranger


Registered: 04/26/20
Posts: 17
Last seen: 3 years, 6 months
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Re: PF Tek: Jar Prep for Pressure Cooker Questions [Re: Mad Hatter]
#26669487 - 05/13/20 09:30 PM (3 years, 8 months ago) |
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Thanks again guys, Just an update, I have pressure cooked 14 1/2 pint jars. It must have worked because I have 0 contamination and I am about 3 weeks in.
I also like leaving it in the PC until inoculation.
Thanks!
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