Adjusting PH to avoid pressure canning starter wort

[Buczekbrewing]

Hello everyone, I currently make my starters ahead of time and can them. I have the luck of having access to an autoclave at work so i can the wort at home and bring it into work to have it truly sterilized. I do this by putting the wort into mason jars and running them through the autoclave. My issue is the 23 psi and close to 260 degrees of heat that this huge autoclave reaches for sterilization. Its breaking my damn jars! I am finding about a 20% loss, meaning every 5 jars full of wort that go into the autoclave only 4 make it through because of glass stress and any imperfections in the glass causing it to break.

I started looking at the guidelines for water bath canning and pressure canning. There seems to be a line of PH 4.6 and below are considered high acid foods and can be water bath canned. Foods with a PH of 4.7 and higher are considered a low acid food and needs to be pressure canned. This brings me to my question; can I lower my post-mashed wort to 4.6 or below with an acid blend, or some other way, to bring it within the water bath canning range?

I forgot to mention that I make all grain starters and after mashing I boil for 15 minutes to avoid excessive break material in my jars. I am wondering if I can introduce some PH lowering additives to the beginning of the 15 minute boil to bring the PH down to 4.5 and not affect the yeast activity later on.

I have found a reference here defining the PH levels of canning methods and http://sophia.smith.edu/~lrizzo/writing/lab6.ppt for yeast health in low PH environments.

Please let me know that your thoughts are.

 

[ajdelange]

Yeast like pH from say 4.0 to 5.0 so there should be no problem with pre-preparing wort down to a pH in that range as far as yeast growth is concerned. Will that stop the growth of spoilage organisms? That I don't know. Pediococcus is pretty durable - a sort of bacterial cockroach. I think you will just have to experiment.

Lots of us have put up wort in home pressure cookers. Can you dial that autoclave back to 15 psi?

 

[pjj2ba]

Try putting your mason jars in a water bath in the autoclave. Most likely they are either heating or cooling too fast (even on slow exhaust). Put the jars in a bath such that the water goes nearly halfway up the jars. This will help to minimize fast temperature swings. You might want to increase the time or the run a little as it takes longer for the extra mass to heat up.

This method also helps to deal with media that is prone to boiling over in the autoclave. Certain media I use just loves to pop the tops off, typically at the end of the cooling cycle. Again the water bath helps to smooth out temperature changes.

 

[fearwig]

I use an electric pressure cooker that gets up to essentially the same PSI/temps, I don't get broken jars unless I try to cool them or something crazy like that. Are they new jars? Maybe your autoclave gets it up to temp faster than my pressure cooker (~20 min). I second what was said about the water bath.

I can starter concentrate, usually 1.080, so one quart jar gives me a two-quart starter. If you concentrate your starter (either bigger grist, more boiling, or combination) you could use more acid and still have a higher reconstituted pH than you would otherwise. I don't think the yeast will be offended by 4.7 either, but it seems like you'd be acidifying your beer less this way (I mean for instance a lager starter can be 15-20% of a batch, so that could get noticeable).

 

[fearwig]

Pediococcus is pretty durable - a sort of bacterial cockroach. I think you will just have to experiment.

Experiment with botulinum though? Maybe OP has some facial wrinkles to spare.

Just occurred to me that you could reboil the starter wort on opening and denature any botulinum toxin, though. Might be a good precaution if you try this. Most other bugs will stink it up and you'll know not to use it, but botulinum is a ninja.

 

[ajdelange]

Experiment with botulinum though? Maybe OP has some facial wrinkles to spare.

I assume (perhaps a mistake) that if he knows about canning he knows pH should be kept under 4.6 (make it 4.5 just to be on the safe side) in order to make it impossible for botulinus to grow. Reducing the activity of water also helps so making the wort stronger is a good idea but you need water activity of less than 0.95 and that's a lot of sugar.

 

[fearwig]

There's a thread on here where someone canned leftover turkey in a tostitos jar... on his stovetop. Most people who responded were cheering him on, and yes, he ate it. Forgetting canned wort could grow botulinum seems pretty tame to me, haha.

 

[ajdelange]

As fearwig (interesting name given the context) says, botulism is not something you want to experiment with. The cover of the notebook in which I keep sausage recipes is labeled 'BOTULUS' in large letters both because that is the Latin word for sausage and to remind me - well the fact that they named the disease botulism makes it obvious. Pass the sodium nitrite please.