Sterilizing steam vs dry heat

[Jeffg353]

As the title suggests... I'm looking into either an autoclave (have also seen pressure cooker being used) or a dry heat sterilizer. Do u guys have a preference or recommendation n why (thoughts or reasoning behind them)?

Also have seen some UV sterilizers while digging around. I'm guessing these don't provide adequate protection?

 

[daylight driller]

I personally prefer an autoclave. The only way I know to truely sterilize your stoppers are with an autoclave. There is some research that shows dry heat is better for glassware than an autoclave though. If you get an autoclave get a decent used one if nothing else (pelton and crane)

 

[Jeffg353]

When using the autoclave do the items come out wet/damp from the steam?

 

[master.on]

As the title suggests... I'm looking into either an autoclave (have also seen pressure cooker being used) or a dry heat sterilizer. Do u guys have a preference or recommendation n why (thoughts or reasoning behind them)?

Also have seen some UV sterilizers while digging around. I'm guessing these don't provide adequate protection?

When using the autoclave do the items come out wet/damp from the steam?

A proper autoclave should have a drying cycle, properly removing moist air. IMO a vacuum pump is the best option.
Otherwise you only have a glorified pressure cooker.

Air removal
It is very important to ensure that all of the trapped air is removed from the autoclave before activation, as trapped air is a very poor medium for achieving sterility. Steam at 134 °C can achieve in three minutes the same sterility that hot air at 160 °C can take two hours to achieve.[9] Methods of air removal include:

Downward displacement (or gravity-type): As steam enters the chamber, it fills the upper areas first as it is less dense than air. This process compresses the air to the bottom, forcing it out through a drain which often contains a temperature sensor. Only when air evacuation is complete does the discharge stop. Flow is usually controlled by a steam trap or a solenoid valve, but bleed holes are sometimes used, often in conjunction with a solenoid valve. As the steam and air mix, it is also possible to force out the mixture from locations in the chamber other than the bottom.

Steam pulsing: air dilution by using a series of steam pulses, in which the chamber is alternately pressurized and then depressurized to near atmospheric pressure.

Vacuum pumps: a vacuum pump sucks air or air/steam mixtures from the chamber. (http://www.astell.com/autoclave-vacuums-explained)

Superatmospheric cycles: achieved with a vacuum pump. It starts with a vacuum followed by a steam pulse followed by a vacuum followed by a steam pulse. The number of pulses depends on the particular autoclave and cycle chosen.

Subatmospheric cycles: similar to the superatmospheric cycles, but chamber pressure never exceeds atmospheric pressure until they pressurize up to the sterilizing temperature.
Autoclave - Wikipedia

https://www.gd-thomas.com/assets/Autoclaves_17000207.pdf

 

[Docd187123]

They both serve different purposes. Any kind of glassware that can tolerate high temps is best suited to dry heat sterilization which also tend to provide depyrogenation as well.

Autoclaves, while they do sterilize some things very good, do not depyrogenate.

 

[daylight driller]

When using the autoclave do the items come out wet/damp from the steam?

If you buy a cheap autoclave odds are that it does not dry. If you get a good autoclave then as stated above it should have a drying cycle. On some of the older (but still very good autoclaves) you will have to crack the door during the drying cycle. One thing to also consider is that you must clean your autoclave properly, its easy to do and most conpanies make and sell their own cleaners some you put in the tank and others you put in the chamber.

 

[master.on]

If you buy a cheap autoclave odds are that it does not dry. If you get a good autoclave then as stated above it should have a drying cycle. On some of the older (but still very good autoclaves) you will have to crack the door during the drying cycle. One thing to also consider is that you must clean your autoclave properly, its easy to do and most conpanies make and sell their own cleaners some you put in the tank and others you put in the chamber.

Cheap pressure-cooker "autoclaves" ain't recommended. But if you buy one, at least buy autoclave tape to make sure they can get to the required temperature. Be aware that doesn't guarentee sterility.
Autoclave tape - Wikipedia

 

[Jeffg353]

A proper autoclave should have a drying cycle, properly removing moist air. IMO a vacuum pump is the best option.
Otherwise you only have a glorified pressure cooker.

Air removal
It is very important to ensure that all of the trapped air is removed from the autoclave before activation, as trapped air is a very poor medium for achieving sterility. Steam at 134 °C can achieve in three minutes the same sterility that hot air at 160 °C can take two hours to achieve.[9] Methods of air removal include:

Downward displacement (or gravity-type): As steam enters the chamber, it fills the upper areas first as it is less dense than air. This process compresses the air to the bottom, forcing it out through a drain which often contains a temperature sensor. Only when air evacuation is complete does the discharge stop. Flow is usually controlled by a steam trap or a solenoid valve, but bleed holes are sometimes used, often in conjunction with a solenoid valve. As the steam and air mix, it is also possible to force out the mixture from locations in the chamber other than the bottom.

Steam pulsing: air dilution by using a series of steam pulses, in which the chamber is alternately pressurized and then depressurized to near atmospheric pressure.

Vacuum pumps: a vacuum pump sucks air or air/steam mixtures from the chamber. (http://www.astell.com/autoclave-vacuums-explained)

Superatmospheric cycles: achieved with a vacuum pump. It starts with a vacuum followed by a steam pulse followed by a vacuum followed by a steam pulse. The number of pulses depends on the particular autoclave and cycle chosen.

Subatmospheric cycles: similar to the superatmospheric cycles, but chamber pressure never exceeds atmospheric pressure until they pressurize up to the sterilizing temperature.
Autoclave - Wikipedia

https://www.gd-thomas.com/assets/Autoclaves_17000207.pdf

They both serve different purposes. Any kind of glassware that can tolerate high temps is best suited to dry heat sterilization which also tend to provide depyrogenation as well.

Autoclaves, while they do sterilize some things very good, do not depyrogenate.

If you buy a cheap autoclave odds are that it does not dry. If you get a good autoclave then as stated above it should have a drying cycle. On some of the older (but still very good autoclaves) you will have to crack the door during the drying cycle. One thing to also consider is that you must clean your autoclave properly, its easy to do and most conpanies make and sell their own cleaners some you put in the tank and others you put in the chamber.

Appreciate all the useful info. Just trying to keep thing as sterile as possible while getting the most out of my money.

 

[master.on]

Appreciate all the useful info. Just trying to keep thing as sterile as possible while getting the most out of my money.

You can always boil vials (and some stoppers too) in hydrogen peroxide
then bake in oven wrapped in Aluminum foil at 400 F (200 C) for 2 hours for redundancy.

The proper time and temperature for dry heat sterilization is 160 °C (320 °F) for 2 hours or 170 °C (340 °F) for 1 hour.
Dry heat sterilization - Wikipedia

Cheap and effective. No autoclave needed.

 

[daylight driller]

I would not recommend putting rubber butyl stoppers into the oven for 2 hours

 

[Jeffg353]

I would not recommend putting rubber butyl stoppers into the oven for 2 hours

I've got the silicone stoppers if that makes a difference.

I remember reading somewhere about guys using alcohol baths. Would this still be necessary if using an autoclave?

 

[superbane]

They both serve different purposes. Any kind of glassware that can tolerate high temps is best suited to dry heat sterilization which also tend to provide depyrogenation as well.

Autoclaves, while they do sterilize some things very good, do not depyrogenate.

Doc can you write up a clear step by step?
Especially with regards to sterilizing stoppers?
Leaving no room for error?
If you have the time?

 

[daylight driller]

I've got the silicone stoppers if that makes a difference.

I remember reading somewhere about guys using alcohol baths. Would this still be necessary if using an autoclave?

No need for an alcohol bath with an autoclave. Autoclaves work on steam and pressure to sterilize. You can also pick up some autoclave bags pretty cheap so you can sterilize a pretty good bit in one patch and have them on hand for later.

 

[Docd187123]

Doc can you write up a clear step by step?
Especially with regards to sterilizing stoppers?
Leaving no room for error?
If you have the time?

Unfortunately the technology isn’t as readily available for sterilizing stoppers 100% for us. At least I’ve yet to see it a lot. Ill PM you what I do for the stoppers when I have the time.

Edit* where ya been Bane?

 

[Jeffg353]

Unfortunately the technology isn’t as readily available for sterilizing stoppers 100% for us. At least I’ve yet to see it a lot. Ill PM you what I do for the stoppers when I have the time.

Edit* where ya been Bane?

If u don't mind I'd like to see this process as well.

 

[Docd187123]

If u don't mind I'd like to see this process as well.

No problema

 

[Dr JIM]

As the title suggests... I'm looking into either an autoclave (have also seen pressure cooker being used) or a dry heat sterilizer. Do u guys have a preference or recommendation n why (thoughts or reasoning behind them)?

Also have seen some UV sterilizers while digging around. I'm guessing these don't provide adequate protection?

Autoclaves, Laminar flow hoods,
Impervious countertops etc tend to overlook the more common sources of PED related infectious complications, which are user technique and the use of UGL products.

The point being, no amount of
hardware sterilization will matter if the product being pinned is “dirty” or the user has an dirty ass, hands, or technique.

Finally with respect to the question posed, all forms of sterilization have advantages and
disadvantages, depending upon the type of hardware used for “brewing”, but in general the following applies;

FIRST all reusable supplies must be thoroughly cleaned to remove any visable residue and then soaked in a “nontoxic” disinfectant. Thereafter one of the following is applied to achieve MEDICAL sterility.

STEAM = Glassware, Surgical metallics
EO = Plastics
Dry Heat = non-surgical Metals

Jim

 

[Jeffg353]

Autoclaves, Laminar flow hoods,
Impervious countertops etc tend to overlook the more common sources of PED related infectious complications, which are user technique and the use of UGL products.

The point being, no amount of
hardware sterilization will matter if the product being pinned is “dirty” or the user has an dirty ass, hands, or technique.

Finally with respect to the question posed, all forms of sterilization have advantages and
disadvantages, depending upon the type of hardware used for “brewing”, but in general the following applies;

FIRST all reusable supplies must be thoroughly cleaned to remove any visable residue and then soaked in a “nontoxic” disinfectant. Thereafter one of the following is applied to achieve MEDICAL sterility.

STEAM = Glassware, Surgical metallics
EO = Plastics
Dry Heat = non-surgical Metals

Jim

Most of the equipment being used is going to be glassware. Have alconox detergent to wash glass before sterilizing. I want to keep everything as clean n sterile as possible. Not looking to take any shortcuts but at the same time I'm not running an actual "lab" (as in sourcing) so don't want to spend an obscene amount of money.

 

[Dr JIM]

Most of the equipment being used is going to be glassware. Have alconox detergent to wash glass before sterilizing. I want to keep everything as clean n sterile as possible. Not looking to take any shortcuts but at the same time I'm not running an actual "lab" (as in sourcing) so don't want to spend an obscene amount of money.

And that’s the point since, for example, few folk understand how obscene the cost can be if depyrogenation is the objective.

Suffice it to say, bc glassware depyrogenation requires several additional steps, I question the benefit of such a pursuit for the average Joe.

Primarily bc bacteria need a media to reproduce in before
endotoxins develop and the oils used to solubilize AAS is a poor
substrate for bacterial growth.


Jim

 

[master.on]

Well-done heat sterilization beats mediocre "autoclaving"

Boiling in hydrogen peroxide, rinsing with alcohol, allow to dry, then baking (not stoppers)
yields great sterility.

Beware of "autoclaves" that leave vials wet, then you make them unsterile again when drying.