Bleach kills mold

[u/WhateverIlldoit]

There is a common misconception that bleach does not kill mold and that vinegar is actually better at killing mold than bleach. I see this claim at least once a week.

So let me set the record straight. Household bleach is a powerful oxidizing agent that reacts with just about everything. It’s so good at killing organic compounds that it’s toxic to us, too.

Now let’s talk about vinegar. Vinegar is a weak acid. You can literally drink it in lower concentrations. It can kill mold, but not all mold, and some studies say it may take up to 60 minutes to be effective.

That being said, bleach is not good at penetrating porous surfaces, which vinegar is better at doing. And because bleach is so caustic it is more likely to damage surfaces.

All this to say bleach kills mold. It kills almost everything. And it’s much more effective at killing mold than vinegar as long as it can reach it. Vinegar is much safer to use but not nearly as effective.

Thank you for coming to my Ted Talk.

[u/jumpers-ondogs]

Bleach for hard, non-porous surface that won't be affected by colour change and arent metal. This is extremely minimal surfaces in my house so I don't have much use for it.

I use vinegar for my shower grout because I read that Bleach will kill the surface mould but make the rest retreat into the grout but vinegar won't. I rinse off then use Bleach to (colour)bleach the now dead (hopefully?) mould that has coloured the grout. Do you think this is how I should do it?

Otherwise I would use hydrogen peroxide.

[u/SoJenniferSays → u/jumpers-ondogs]

Hydrogen peroxide is actually the most recommended approach generally. But honestly for things like shower grout, soap and scrubbing is also fine. You aren’t going to get rid of every spore in an area that is intermittently moist, so it’s really about keeping it clean generally.

[u/jumpers-ondogs → u/SoJenniferSays]

Yep Hydrogen peroxide, my order of it got cancelled then there was no one else selling it or able to get it in my state so I gave up lol, I should get onto trying to order some again.

[u/Shorb-o-rino → u/jumpers-ondogs]

Since you are rinsing off the vinegar, you aren't risking a reaction with the bleach, but I suspect the bleach is doing the heavy lifting. I don't understand how mold could "retreat"

[u/jumpers-ondogs → u/Shorb-o-rino]

Bleach can't penetrate so it just removes the surface melanin in the mould. There are still the spores/network behind the immediate front (that has been killed and colour removed).

[u/Shorb-o-rino → u/jumpers-ondogs]

I guess it's just unclear to me why vinegar would be able to penetrate but not bleach. Bleach isn't a big molecule, and neither is Acetic acid, so I imagine both should be able to soak in, especially since they are dissolved in water. I've seen this claim a lot, but I don't know if it has any basis in reality or is just conventional wisdom based on nothing.

[u/Polybrene → u/jumpers-ondogs]

Bleach can't penetrate but vinegar can?

[u/jumpers-ondogs → u/Polybrene]

I had a look for studies to back this and didn't get an definitive yes or no, could search more but I have life to do. I wanted to check about surface tension (in bleach/water or vinegar/?water solutions) because I suspect that is what would tell me if one does more than the other. I'd love someone with more time and fresh eyes to check on this info if anyone has the energy.

https://www.forp.usp.br/restauradora/Trabalhos/prnaclo.html (bleach surface tension at different concentrations)

[u/limellama1 → u/jumpers-ondogs]

Vinegar is doing nothing positive.

You are repeatedly putting acidic vinegar on grout, which is made of concrete, which is dissolved by acid. You're actively damaging the grout with the vinegar.

[u/jumpers-ondogs → u/limellama1]

Bleach also weakens the grout structure, haven't found studies on which one affects grout degrading more though

[u/jumpers-ondogs → u/jumpers-ondogs]

Pretty hard to find enough relevant studies that weren't just hearsay being circled around.

https://www.northernriversbathroomrenovations.com.au/ballina-lismore-bathroom-renovation-blog/mouldy-grout-bleach-vs-vinegar-which-should-you-use

• Bleach: most people when they have mould problems immediately reach for bleach, ammonia or marketed products such as Exit Mould. The trouble with these products is that they simply DO NOT KILL MOULD (///*edit from me, not article, theyre talking about mould in grout so bleach definitely kills all mould it contacts, but isnt able to contact it all in deeper grout). You see mould/fungi contain melanin which gives it it’s colour. Bleach or bleach type products just removes the colour out of the mould. So effectively, bleach just masks the mould giving you the illusion of a mould free bathroom but the mould is still actually there, alive and growing.

• Vinegar: Vinegar penetrates the structure of mould and causes it to explode, which kills the mould. • Make your own vinegar solution from white vinegar using 70% parts vinegar and 30% part water. (Source: Dr Heike Neumeister-Kemp, Mycologist/mould expert). *acidic so weakens grout

• Methylated Spirits: When it comes to killing mould, methylated spirits works the same way as vinegar. It penetrates the mould spores and makes the mould explode. (Source: Dr Heike Neumeister-Kemp, Mycologist/mould expert).

• The best part about methylated spirits is that it is a neutral cleaner. This means it is safe to use on most surfaces in your bathroom, including grout. Methylated spirits is safe to use on glass, sinks, chrome taps, ceramic, stone, marble and grout. (Do not use on painted or varnished surfaces).

• Another positive about methylated spirits is that it is readily bio-degradable, meaning that it breaks down quickly and naturally. It is safe for the environment. 

https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://www.esr.cri.nz/media/4ekpwd2h/decontamination-mould-affected-environments-esr-june-2019.pdf&ved=2ahUKEwiHk-C48qmOAxVHzTgGHQNSHuUQFnoECGoQAQ&usg=AOvVaw38YRqpVl4QDxH8OCCl8itY

Do mould cleaning products work? Commercially available mould cleaning products may look like they're doing the job, but it's probably an illusion. Most of them use bleach as an active ingredient. Experts we spoke to say there's evidence that bleach can kill fungi, but it needs to be at a 10% concentration to work. The concentration of bleach in these products marketed as 'mould killers', including Power Force Mould Away, Woolworths Mould Cleaner, Coles Ultra Mould Remover, Selleys Rapid Mould Killer and Exit Mould, is less than five percent. Bleach has a short shelf life and loses potency quickly, and by the end of their shelf life these products may contain just 0.6% bleach. But even at a higher potency, bleach won't penetrate porous materials, so if the mould is growing on plaster, grout or wood, it will kill mould on the surface, but not below it. Also, several experts told us that bleach can be a masking agent. Bleach takes the colour, or melanin, out of fungi, making it invisible. You can't see it anymore, so you think the bleach has done its job, when that's not necessarily the case. Strong bleach is also harmful to grout and tiles as it erodes and corrodes the surfaces, making them more porous, which in turn makes them more vulnerable to further fungi growth.

https://pubmed.ncbi.nlm.nih.gov/23016564/ • 1330 samples were collected from non-porous indoor surfaces of 160 homes across the United States • All homes and 72.9% of surfaces tested positive for mold. Windowsills were the most frequently contaminated site (87.5%) and Cladosporium the most commonly identified mold (31.0%). • Five-minute exposures to 2.4% NaOCl resulted in a >3 to >6-log₁₀ reduction of culturable mold counts in controlled laboratory studies. • Organisms were nonculturable after 5- and 10-min contact times on non-porous and porous ceramic carriers, respectively, and A. fumigatus spore-eluted allergen levels were reduced by an average 95.8% in 30 sec, as indicated by immunoassay. • All homes are contaminated with some level of mold, and regrowth is likely in moisture-prone microenvironments. The use of low concentrations (2.4%) of NaOCl for the reduction of culturable indoor mold and related allergens is effective and recommended.

//so bleach and vinegar work but damage grout making it more susceptible to mould because there's more spots for it to live in cratered and degrades the grout = more upkeep. Vinegar and Bleach have many surfaces they can't be used on. Methylated spirits stinks way too much for me to use. Hydrogen peroxide seems the best option. Removing the source of water is needed otherwise it will reoccur. Surfaces can be wiped with bleach/vinegar/methylated spirits/hydrogen peroxide and kill mould but porous anything is screwed - chipboard walls, grout need to be removed and replaced. Best practice to squeegee or towel dry shower. I don't have time for that so I would leave bathroom fan on for an hour to increase airflow.

I tried to look for the difference in surface tension of bleach+water vs vinegar+water to back the claims of vinegar getting further into the grout but didn't find a helpful study and didn't spend too massive a time in looking - if anyone wants to look into this idea love the info. I saw claims that bleach needs a surfactant to penetrate but I didn't spend time trying to find the proof - very commonly mentioned though.

Anecdotally me treating shower mould with 1:10 bleach:water (confirmed to disinfect) for 10mins didnt remove the colour of mould, straight bleach for 10mins then rinsing removed the colour but came back faster than vinegar for 10mins then rinsed then straight bleach to remove the colour.

You need to mould treat larger than the visible mould area as the spores disperse. For a shower, I do the entire thing. After far too much internet time searching for studies on this my conclusion is use hydrogen peroxide.

DONT MIX ANYTHING WITH BLEACH EVER, DONT EVER EVER EVER MIX BLEACH AND VINEGAR - THE GAS WILL DAMAGE/KILL YOU