Build a pressurized container to infuse herbs

[uscmedina]

TL;DR Summary

I want to build an air tight pressurized container to be used to infuse herbs

First off I would like to thank anyone and everyone that reads and or contributes any guidance to my problem.

I want to build a pressurized container that can hold 10lbs of an herb, ex. mint , so I can infuse it with a flavor, ex. vanilla.

I have the infusion process worked out.

I just need an air tight container that I can apply pressure so that my Vanilla extract can be absorbed by the mint.
My first thought was to use an old refrigerator since it already has an air tight seal. Then add a mechanism that would apply pressure into the refrigerator but I do not know if the refrigerator would hold up to the constant change of pressure.

I am open to have a box built. Hard plastic would be great but I do not have a large budget and I am afraid that a custom made box of this kind will be expensive. I considered a Stainless Steel container as it would be less expensive to have made.

Once again, thank you to one and all.

 

[.Scott]

I would start with something like this:
60 PSI Air pressure paint tank ($100).

There are many air pumps for under $50 that can produce 60psi. Then you'll need valves and connectors.

Of course, you haven't told us how much pressure you need.

Pressure cookers generally operate well below 20 psi.

 

[DaveE]

It might be hard to have high pressures in something as large as a refrigerator. There are a lot of square inches in a refrigerator door. Let's say your door is 2' x 3' at 60psi that is 51,840 Lbs of force to contain. Roughly like trying to support about 18 Honda Civics.

Edit: that's 60psi gauge pressure, i.e. in addition to the 15 psi of normal atmospheric pressure.

 

[russ_watters]

I want to build a pressurized container that can hold 10lbs of an herb, ex. mint , so I can infuse it with a flavor, ex. vanilla.

We need to know what pressure you need for this process.

My first thought was to use an old refrigerator since it already has an air tight seal. Then add a mechanism that would apply pressure into the refrigerator but I do not know if the refrigerator would hold up to the constant change of pressure.

Air tight doesn't mean pressurized. A refrigerator can't hold a significant pressure.

 

[uscmedina]

Thank you for your insights.
As far as what pressure I want or need that is something that I need to work out through trails.
I understand the constraints of using a refrigerator. So, if I build a S/S box would that work 24"x24"x24"?
Again, Thank you for your input in this matter. I appreciate your time and assistance.

 

[.Scott]

Thank you for your insights.
As far as what pressure I want or need that is something that I need to work out through trails.
I understand the constraints of using a refrigerator. So, if I build a S/S box would that work 24"x24"x24"?
Again, Thank you for your input in this matter. I appreciate your time and assistance.

That $100 device is going to be way cheaper and safer than anything you can build in your garage.
Also, it will give you 60 PSI - plenty of room for "trials".

 

[.Scott]

You say you want to build an "air tight pressurized container".
"Air tight" I understand.
But pressurizing a container (without heating) for the purpose of infusing vanilla flavor sounds decidedly sketchy.

What exactly is this pressure for? Is it just to make sure that the inside does not become contaminated. Or do you imagine that the pressure will directly assist in the infusion?

For the most part, the pressure levels that would be considered safe for home use will have no effect on the mixing of solids and liquids. The vanilla has a vapor pressure of less than 1 Pascal - a tiny fraction of normal atmospheric pressure.

If the herbs include gaseous cavities in their internal structure, then perhaps pressure will assist with "infusing".

 

[uscmedina]

I appreciate your thoughtful insight. I have a method that can infuse herbs with other flavors.
The pressurized container I want to build is for both of the above stated reasons but primarily for the infusion process.
I will not be doing this in a home but a 7.5k commercial warehouse, side project.
The example of mint & vanilla is just 1 of the infusions I have already successfully made but there are many others I want to play with.
Thank you for your time in this matter.

 

[uscmedina]

I would start with something like this:
60 PSI Air pressure paint tank ($100).

There are many air pumps for under $50 that can produce 60psi. Then you'll need valves and connectors.

Of course, you haven't told us how much pressure you need.

Pressure cookers generally operate well below 20 psi.

At this point, I do not know how much pressure I will need.
Based on your info I think I will have S/S box made with a door that seals air tight and connect pressure tank with a digital read out of the pressure being added to the container so I can experiment with the best PSI.
If you see any faults in this plan or have any suggestions I am all ears.
Thank you

 

[berkeman]

I have a method that can infuse herbs with other flavors.
The pressurized container I want to build is for both of the above stated reasons but primarily for the infusion process.

Sorry if this is a dumb question (or was mentioned earlier in the thread and I missed it), but would a traditional pressure cooker work? I don't know what PSIg ratings most pressure cookers have but that seems to be what pressure cookers are for, no?

My wife loves her InstaPot, which apparently is a combination of pressure cooker and other cooking features all in one appliance. Is there maybe an InstaPot recipe for doing this herb infusion already?

https://www.goodhousekeeping.com/ap...eviews/g204/electric-pressure-cooker-reviews/

https://www.target.com/p/instant-pot-duo-6qt-7-in-1-pressure-cooker/-/A-50608360?ref=tgt_adv_XS000000&AFID=google_pla_df&fndsrc=tgtao&CPNG=PLA_Appliances%2BShopping_Local&adgroup=SC_Appliances&LID=700000001170770pgs&network=g&device=c&location=9032181&ds_rl=1246978&ds_rl=1247068&ds_rl=1248099&gclid=CjwKCAjw7-P1BRA2EiwAXoPWAxSNUC9bPNLWorUiqFEVS-nDhs3ytUcWlKD765C7owa-ZNkhIOtP8BoCmRQQAvD_BwE&gclsrc=aw.ds

 

[.Scott]

When you say "S/S Box", are you talking about one of those electrical boxes?
In any case, how are you going to make piping connections that will not leak and handle the pressure?
If you are dealing with more than 1 psi, do you plan on putting in a relief valve?
How about a pressure gauge?

 

[uscmedina]

I welcome all questions and info
There are 2 issues with the pressure cooker
1- they are small and I want to be able to do at minimum 10lbs per session
2- I do not want to cook the herbs I just want to infuse them with a complimentary flavor essence

Scott,
Thank you for your time and interest in my little side project.
Sorry, I used S/S without identifying what that stood for, Stainless Steel. A friend of mine manufactures S/S restaurant equipment so he can build a container with a door that seals air tight plus I figured it is clean non-porous and easy to clean and maintain.
My friend can make anything out of S/S, Ideally I would want it to be made out of hard plastic but from my research it is quite expensive to have a mold made then have it poured just for a few boxes. Hence the S/S box.
Yes I did plan to have a relief valve added to the container.
I appreciate your time and questions.

 

[uscmedina]

When you say "S/S Box", are you talking about one of those electrical boxes?
In any case, how are you going to make piping connections that will not leak and handle the pressure?
If you are dealing with more than 1 psi, do you plan on putting in a relief valve?
How about a pressure gauge?

Scott,
Thank you for your time and interest in my little side project.
Sorry, I used S/S without identifying what that stood for, Stainless Steel. A friend of mine manufactures S/S restaurant equipment so he can build a container with a door that seals air tight plus I figured it is clean non-porous and easy to clean and maintain.
My friend can make anything out of S/S, Ideally I would want it to be made out of hard plastic but from my research it is quite expensive to have a mold made then have it poured just for a few boxes. Hence the S/S box.
Yes I did plan to have a relief valve added to the container.
I appreciate your time and questions.

 

[berkeman]

Stainless Steel. A friend of mine manufactures S/S restaurant equipment so he can build a container with a door that seals air tight plus I figured it is clean non-porous and easy to clean and maintain.

That's great. I had food safety worries about your post (and the paint container suggested earlier), but if your friend is familiar with food safety in the choice of materials and fabrication techniques, that's a relief for me.

 

[DaveE]

You mean a really strong S/S box. Be mindful of the forces involved.

If you do go that route you should probably do a hydrostatic pressure test before you use it so you'll know it won't explode. Test with some additional pressure as a safety margin.

 

[Tom.G]

I don't know what PSIg ratings most pressure cookers have

Waaay back in my chilhood days, the stovetop pressure cooker had a weight the fit over a vent in the cover... it had three positions labelled "5", "10", "15" lbs.

A quick Google search found a statement that most are 15 lbs.

@uscmedina
Be aware that most (all?) states require both a license to design/build, and a certified welder for, pressure vessels above a certain pressure; details would vary by state. You friend may be very good at restaurant kitchen cabinets but sheet metal and pressure vessel construction are different worlds. Kitchen cabinents don't explode, .

I strongly urge you try commercially available vessels for you trials, then pursue larger vessels when you know the pressure requirements.

Please, be safe.

 

[russ_watters]

Thank you for your insights.
As far as what pressure I want or need that is something that I need to work out through trails.
I understand the constraints of using a refrigerator. So, if I build a S/S box would that work 24"x24"x24"?

One of us has to guess what pressure you need to use. I would have hoped it would be you, but since you are forcing us to do it for you, I suggest you try pressures up to 15 psi using a pressure cooker, as @berkeman suggested. But once you get your system set up, only you can turn it on and set the pressure. Eventually, you will have to be the person to make the choice.

There are 2 issues with the pressure cooker
1- they are small and I want to be able to do at minimum 10lbs per session
2- I do not want to cook the herbs I just want to infuse them with a complimentary flavor essence

Here's a 21 quart pressure cooker:
https://www.plantbasedpros.com/prod...T6JqCFW0ci28gVxPN4RBwt1whPUepfAhoC25IQAvD_BwE

If it doesn't allow setting the pressure without heating, then you might also try a beer keg system. I use a 1.75 gallon system that pressurizes up to 30psi. 1.75 gal of mostly water is about 15 lb.

Based on your info I think I will have S/S box made with a door that seals air tight and connect pressure tank with a digital read out of the pressure being added to the container so I can experiment with the best PSI.
If you see any faults in this plan or have any suggestions I am all ears.

Yes, the fault in this plan is that the idea is so badly flawed that you have about as good a chance of killing yourself as you do of succeeding in making a functioning rig. The math isn't hard: even just 1 psi of pressure on a full sized refrigerator door is a force of 2,500 lb. Even if you could reinforce it to hold that much pressure, if the door pops open with you standing in front of it, it will kill you.

Seriously. You need to:
1. Decide what pressure you want to test to.
2. Buy a proper pre-engineered device/product that meets your needs.

You cannot build your own pressure vessel and we do not allow development of dangerous devices here: we won't be party to/liable you hurting/killing yourself.

So please. Put some more effort into this or we'll have to shut down this discussion.

[edit]
FYI, if you think I'm exaggerating; for 1 psi on the door to kill you, you'd have to be standing right in front of it and get hit the right (wrong) way. But up to 15 psi (in the range we're talking) is typical for autoclaves, for example, and they do indeed occasionally kill people:

Employees #1 and #2 were assigned to unload an autoclave. While Employee #2's back was to the autoclave, Employee #1 opened it while it was still under pressure. A number of safety mechanisms failed, including the locking ram, which prevents the door from being opened: it was incorrectly covered...

Employee #1 was pronounced dead at the scene. Employee #2 sustained lower back injuries from being struck in the back by carts in the area.

https://www.osha.gov/pls/imis/accidentsearch.accident_detail?id=170340327

 

[.Scott]

My suggestion for keeping the pressure container clean and the food safe is to put the vanilla/food mixture in a plastic bag before stuffing it into the pressure vessel.

For $100 (plus the air pump) you are saving yourself a lot of work, a lot of experimentation, and perhaps your life. You'ld be staying on the right side of the law, pressurizing without heating, and allowing yourself a wider psi range than other options.

And if my guess is correct, that 60 psi for 2 days when compared to 0 psi for 2 days will convince you that the pressurization does nothing for you - but let us know.