Sterilization Methods

	There are several likely vectors for contamination during brewing: failing to sterilize the top of the vials prior to filling with the syringe, failing to adequately sterilize the glassware used during this process, and airborne bacteria getting into the brew during the mixing process. Ensuring adequate sterilization will ensure that your final product is safe for use.
	For sterilization of the top of the vials: just do it. Don’t be lazy, swab it with an alcohol wipe every time you insert a needle into it.
	For the airborne bacteria, a still air box can be used to minimize that risk. There are resources online on how to construct one easily. Should cost you less than $10.
	For the glassware, the following sterilization methods will work on all forms, assuming they are all made of borosilicate glass.

	The smallest bacteria you can come in contact with is mycoplasma, the bacteria family that causes walking pneumonia. It is the smallest form of bacteria, and has a size of 0.15-0.3 micron. While incredibly unlikely to be present at home, if you wish to ensure that you completely and totally sterilize your materials, you will have to use a method beyond filtration.

Materials to use
	For all glassware, borosilicate glass is ideal. It has a high resistance to thermal shock, and a high temperature at which it is not longer usable. It is able to withstand 500°C maximum operating temperaturei and a temperature differential of 165°C before it shatters from the shock.ii Therefore, for glass vessels not under pressure, all forms of sterilization in the following information is able to be performed with this type of glass.

Filtration
	When filtering a liquid to be sterilized, you must ensure that you have a filter that only allows for the smallest of particles. Best bet is 0.22 micron or 0.2 micron filters. In the context of filtration, either size is adequate for sterilizing the liquid. That size will ensure that almost no bacteria and particulate will make it’s way into the final product, assuming contamination does not happen after the fact. iiiThe exception, however, is mycoplasma. Mycoplasma is a bacteria which varies in size, from 0.15 micron to 0.3 micron. Unfortunately, this means that total sterilization via filtration may be ineffective when using a 0.22 or 0.2 micron filter. There are 0.1 micron filters, however a drawback may be that those filters will increase the amount of time it takes to filter, as to potentially be unreasonable for filtration at home.

Microwave
	Sterilization via microwave will destroy or neutralize all bacteria and viruses within a sample.iv The time as reported by the CDC in order to ensure adequate sterilization is 5 minutes in a 600W microwave. However, home microwaves may have uneven heating throughout. Therefore, using this method with another sterilization method may be the best bet for adequate results. The bacteria killed also includes mycoplasma.
	This method, along with all other heating methods, is not suitable for the final mixture as it may cause damage and breakdown. However, it is a good practice is to microwave your materials immediately prior to brewing. This will allow the most minimal time for bacteria to “take hold” on the equipment, and decrease the risk of contamination.



Dry Heat
	Dry heat sterilization is achieved by heating up the instruments to a temperature of 160°C (320°F) for 2 hours or 170°C (340°F) for 1 hour, causing the bacteria and viruses to denature.v The advantage of this system is that electric ovens are readily available for most people at home. The disadvantage is the inability to control how even the temperature within an oven is as well as the assurance as to the oven’s ability to reach that temperature. This is best used on the instruments immediately prior to beginning the mixing process, however the instrument should be allowed to cool down before beginning, due to the sensitivity to high levels of heat that some of the liquids have.vi

Wet Heat
	This is the most common mode of sterilization in a laboratory environment. This is how autoclaves work. The main action is that, under pressure, cells are forced to coagulate in the presence of intense heat and steam, thereby killing them.
	In a home environment, an autoclave is not accessible due them being prohibitively expensive. However, a home version that works on the same principle is a pressure cooker. However, the only pressure cooker able to eliminate all forms of bacteria was found to be Instant Pot.vii In order to kill all bacteria, the instant pot was required to remain at working pressure and temperature for a minimum of 1 hour.viii

Conclusion
	Due to the availability of various methods of sterilization for instruments, including items you likely already have, there is no excuse to not sterilize your materials prior to working and mixing. Don’t be dumb, sterilize your shit.

https://www.schott.com/d/tubing/9a0f5126-6e35-43bd-bf2a-349912caf9f2/schott-algae-brochure-borosilicate.pdf
https://en.wikipedia.org/wiki/Borosilicate_glass
https://www.sterlitech.com/blog/post/defining-a-pore-size-and-sterile-filtering-0-2-microns-vs-0-22-microns-whats-the-difference
https://www.cdc.gov/infectioncontrol/guidelines/disinfection/sterilization/other-methods.html
https://en.wikipedia.org/wiki/Dry_heat_sterilization#cite_note-3
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC480155/?page=2
https://instantpot.com/who-knew-that-instant-pot-can-provides-scientific-grade-sterilization-actually-we-did/
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0208769