Wort Under Pressure cover

Wort Under Pressure


One of my least favorite aspects of brewing beer is making a starter a few days before. While not the hardest thing in the world to do, it can be a colossal pain in the ass to lose an entire night (and kitchen counter top) to DME. So how do you make a process so crucial to a healthy fermentation more convenient? Batch pressure canning!

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Pressure Canning Wort Starter

Pressure Canning Wort Starter

One of my least favorite aspects of brewing beer is making a starter a few days before.

While not the hardest thing in the world to do, it can be a colossal pain in the ass to lose an entire night (and kitchen counter top) to DME. So how do you make a process so crucial to a healthy fermentation more convenient? Batch pressure canning!

Bite The Bullet

A while back I was complaining about making my yeast starter as I often do and a friend of mine, Greg Nylen, of Barley Forge Brewing, mentioned that he makes a large batch of wort and pressure cans it in mason jars.

That’s when Drew Beechum, homebrewer and writer, chimed in (check out his latest book Experimental Home Brewing!). He sent me a link to a piece he wrote about pressure canning wort, with a step by step guide detailing exactly how to do it. I bit the bullet and ordered a pressure canner off of Amazon, which turned out to be rather pricey, but at least it was All American. ‘Merica is important.

Here’s how it went.



I’m going to take you through what I did during my first round of pressure canning. The process is relatively simple though you really need to make sure you understand how pressure cookers work and adhere to all safety precautions. I encourage you to check out Drew’s piece on pressure canning starter wort and also Michael Tonsmeire’s piece on the same subject on his blog, The Mad Fermentationist.

Acquire Dry Malt Extract (DME), Yeast Nutrient, Pressure Canner/Cooker, Mason Jars, and Lids

Clean Your Jars And NEW Lids

This is one part you don’t want to skimp on. Make sure your mason jars are completely clean and the lids you use are brand spanking new.

This goes with any sort of canning, but the seal around the lids is technically only good for one use. The penalty for risking it is spoiled food and botulism poisoning. The easiest way to clean everything is by boiling though you can also run your jars, not lids, through the dishwasher with heat dry selected.

Provided the dishwasher finishes close enough to canning time, you can just leave them in there until you’re ready to pull each jar. The lids should be boiled in a saucepan on the stove for 10 min – letting them sit in the heated water until you are ready to use them.

Prep Your Pressure Canner

Pressure canners have the potential to be very dangerous if directions are not followed correctly. Make sure you read the directions and do a dry run prior to canning your wort. Understanding how the gauge functions is easy, but the pressure regulator rattling is something that needs to be witnessed to understand.


Bad Rattling – Temp/Burner Is Too High

This video of the regular weight does a pretty good job of illustrating the rattling, but it does feel more high stakes in real life. So…follow the directions, do a dry run, and then go to the next step.


Good Rattling – Temp is Just Right

Rattle Should be 1-4 Times per minute.


Fill Your Freshly Cleaned Mason Jars

Fill Your Freshly Cleaned Mason Jars

Follow Drew’s guidelines for filling each mason jar. I chose to make quart starters as I typically do 10 gallon batches and measure my starters in liters. Home brewing is really all about continuously mixing metric and imperial measurements. I opted out of adding a hop pellet, but it’s an optional addition.


The basic process here is to measure out the DME and Yeast Nutrient by adding them directly to the mason jar while it sits on a scale.

They can then each be filled with hot or cold filters water. Once the jar is full, make sure to fill the 3/4″-1″ from the top as overfilling or under-filling may cause issues. A hot lid that has been boiled in a water bath can now be added along with a hand tightened collar. It’s important to not tighten the color too much as it may cause the lid to buckle.

Drew’s Pressure Cooker Starter Recipe

Yields 1 Quart. (Half DME for pints)

3.2 ounces (by weight) Light DME

1 pinch Yeast Nutrient

1 small Hop Pellet. (Optional)

Water to fill.

Weigh DME into jar and toss in the super food and hop pellet.

Fill with water until just ¾” below the top of the Mason jar. (Generally I go right to the line where the ring snugs into the jar)

Place a lid and ring onto the jar and hand-tighten until snug, but not overly tight.

Shake to mix.

Place with other jars into a pre-heated pressure cooker. Make sure jars are sitting on a canning rack or excess rings. Sitting the jars on the bottom may cause them to crack.

Close the lid onto the pressure cooker leaving the vent open.

Allow the cooker to steam out of the vent to purge air.

Close the vent and allow the cooker to rise to 15 p.s.i.

Maintain 15 p.s.i. for 15 minutes and allow to cool naturally.

Remove jars from the cooker and allow to cool thoroughly before using.

Pressure Canning Step By Step

Pressure Canning Step By Step

It’s time to get the pressure canner going. Be sure to evenly seal the lid (follow your canners specific directions) and ensure that it’s secure before starting.

Pay Careful Attention

Pay Careful Attention

My canner instructions say to heat the canner on high until a steady column of steam escapes from the outlet for 10 minutes. Once the 10 minutes are up I can then add my regulator weight (at 15 psi), which will drive up the pressure and temperature. This is really the point where you need to devote your entire attention to the process as an unwatched pot during this stage may result in serious injury.


You’ll notice the pressure gauge reading steadily rising, which may take about 15 minutes or so.

Once the pressure hit 15psi the regulator weight will begin to rattle. You can now start your 15 minute timer.

The goal here is to adjust the temperature so that the rattle is short, controlled, and happening 1-4 times a minute.

Reducing Pressure

When your 15 minutes is up, turn off the heat, and let it cool down on its own. This part of the process does take a while and cannot be rushed.

No water baths, cold towels, or ice. Part of the pressure canning process is this last part of letting everything equalize on its own. Keep on eye on your pressure gauge as it approaches zero. As soon as it hits zero you’ll need to remove the regulator weight with a hot pad and let sit for 2 minutes. When this is done you can carefully remove the lid with opening pointed away from you.

Escape Valve

Escape Valve

Remove Jars

Having a basic canning tool set is really helpful and should probably be mandatory for using a pressure canner.

Use the jar lifter tongs to gently remove each jar from the canner and place them on a insulated surface or cookie sheet so they can cool. Jars will be extremely hot and will take some time to come to room temperature. It’s best to find a place out of direct sunlight.

As the temperature drops and equalizes for each jar, the lids will vacuum pop inwards – this is how you know the seal is happening. To make sure the seal is good, lightly unscrew each collar. For any jars that do not seal properly – lid pops up, buckles, or never gets sucked down – either reprocess these jars or use immediately.

Storage & Use

Storage & Use

Let cool completely and then store in a cool dry place. Starter wort is ready to use and will keep 6-12 months, likely a lot longer. Before use, sanitize the outside of the jar with sanitizer and alcohol.


This method is great. The pressure canner buy in is high depending on the make and model.

There are economy versions you can find that’ll get the job done, but the size may prevent you from making the volume that’ll make it worth it. My canner will fit (7) 1 qt. mason jars, which works well for me. The idea that I can prep for (7) 5-gallon batches or (3.5) 10-gallon batches in one sitting is reason alone to adopt this method.



I had one jar buckle, which was a bummer, but I just repurposed the wort for something else.


Another advantage to using a pressure canner is detailed in Michael Tonsmeire’s post.

He cans a large quantity of smaller 8oz mason jars so he can pull bottle dregs on the fly and grow starters up from there. The value of having smaller, sealable mason jars for trips to wild/sour breweries or bottle shares cannot be understated. Obviously this is a short term solution though as these jars aren’t really ready built to handle pressure. He suggests to vent regularly although you could alternately use a mason jar pickler setup.



P.S. If you’re going to invest in a pressure cooker, use it for more than just brewing. Home canning is awesome and should totally be part of the home brewers arsenal.