08-30-2023 | Lisa Bronner

What Can You Mix with Dr. Bronner’s Sal Suds?

Someday I’m going to make myself a set of t-shirts that say, “Chemistry happens!” I say it a lot and think it even more. Chemistry is all around us, and I’m not talking about the romantic kind. Cooking is chemistry, housecleaning is chemistry, body care is chemistry. The trick is to make sure the chemistry is happening in your favor.

There is a category of customer questions I receive that I call “the mixers.” The question starts, “Is it ok to mix Sal Suds with…” I have learned a lot myself over the years doing the research in answering these questions and have engaged chemists to help me understand what is going on at the molecular level. I send a huge thanks to my colleagues Laura Aung and Ivan Villalobos in Dr. Bronner’s Research and Development team for their patience in answering all my many mixer questions.

My post on Castile mix-ins that I wrote in 2018 is still one of my most visited and most commented on. I am finally able to provide a comparable chart for Dr. Bronner’s Sal Suds Biodegradable Cleaner, or “Sal Suds” for short.

What is Sal Suds

Sal Suds, our biodegradable household cleaner developed by my dad Jim, is my go-to product for cleaning my house. I clean everything with it. Dishes, laundry, floors, bathrooms, pre-stain laundry treatment. I always travel with a 2 oz. bottle of it, and I always need it for something. For its multitude of uses, see the Sal Suds Dilution Cheat Sheet.

In almost every situation, Sal Suds works great all by itself. However, it is not uncommon for people to want to add things to it. Are they being creative? Do they think they’re improving it? Are they just having fun? Maybe some of each!

Sometimes it is ok to mix things into Sal Suds, and sometimes it is not. Please refer to this chart of various substances I’ve been asked about over the years by readers:

Ingredient	Intent	Recommended?	Explanation
Baking soda	To create a scrub- bing cleanser	Yes	Baking soda adds a soft abrasion to the cleaning power of Sal Suds. This makes a good scrubber for grimy sinks and fabrics. In laundry, it is a whitener and deodorizer.
Chlorine bleach (aka sodium hypochlorite)	To remove stains & whiten fabrics	No	Bleach reacts with Sal Suds and forms a white precipitate (solid). Bleach in general is highly reactive. Unless you are very well-versed in chemistry, never mix bleach with anything except pure water. Because sodium hypochlorite poses such a great risk to people, pets, and planet, I have always found another option.
Borax	To boost surface & laundry cleaning	Yes, but try baking soda first	Borax does not react with Sal Suds and can be an effective laundry addition. However, I always recommend using the least intensive means possible when cleaning, and with its slightly higher pH and skin irritating potential, borax is more intense than baking soda. Try baking soda first as a laundry booster.
Dr. Bronner’s Castile Soap	To create a custom scent	Not problematic but not productive	Combining the Pure-Castile Soap with Sal Suds is not reactive, but I don’t see the point. If it’s the scent of the Pure-Castile Soap that’s desired plus the stain-fighting power of the Sal Suds, I recommend using essential oils with the Sal Suds.
Essential oils	To create a custom scent	Yes	This can make green cleaning even more fun! Start with just a few drops of essential oils and increase as preferred. Look for organic pure essential oils.
Hydrogen Peroxide (H2O2)	To remove stains, whiten fabrics, disinfect	Not problematic but not effective	Hydrogen peroxide is listed on the Environmental Protection Agency’s (EPA) Safer Chemicals Ingredient List as a safer antimicrobial and an oxidant. When mixed with Sal Suds, hydrogen peroxide quickly dissipates into oxygen and water. Hydrogen Peroxide is a useful part of the green cleaning arsenal, but use it separately from Sal Suds.
Lemon juice	To boost cleaning	No	Lemon juice is an excellent addition to your green cleaning toolbox but, like vinegar, not a good partner for Sal Suds. Also, lemon juice is not shelf stable. Left at room temperature it will ferment and outgas. In a closed bottle, it will explode. Ask me how I know.
Lemon oil (and other citrus oils)	To customize scent	Yes	I am specifically calling out lemon essential oil, in addition to my general statement about essential oils, because of the confusion I’ve heard from readers over why lemon oil is OK to mix in but lemon juice is not. Lemon juice is an acidic, water-based liquid extracted from the pulp of the fruit. Lemon oil is extracted from the rind of fruit. Oils do not have a pH, which is a measurement only of water-based solutions. Therefore, the acid/base reaction is not possible.
Oxygen Bleach	To fight stains	Not reactive but ineffective	Oxygen bleach is most effective against stains when dissolved alone in water as a presoak. Mixing it with soap or detergent accelerates the destabilizing of the hydrogen peroxide, leaving mere washing soda behind. For best results, presoak laundry with oxygen bleach and water, then launder with Sal Suds.
Ethanol or isopropyl alcohol (including any drinking alcohol)	To add disinfect-ing capa-bility	No	Alcohol is an antiseptic and disinfectant listed on the EPA’s short list of safer antimicrobial cleaners. Alcohol reduces the foaming of Surfactants (Sal Suds) and, at higher concentrations, impedes its cleaning ability. Rather than combining the alcohol with Sal Suds, the WHO and the CDC recommend a two-step method: wash surfaces first (such as with the GIY All-Purpose Cleaning Spray) and then treat with the alcohol. Make sure you read instructions about the amount of time alcohol needs to contact surfaces. If you wipe it off too quickly, it will be ineffective. The time varies based on the percentage of alcohol. Remember alcohol is highly flammable.
Salt	Scrubbing agent	Not reactive but thickens	Salt can be useful in scrubbing cast iron skillets, but take care not to use it on surfaces it can scratch. It is fine to add to diluted Sal Suds, but it will thicken undiluted Sal Suds significantly.
Vinegar	To boost cleaning	No	Vinegar reduces Sal Suds’ cleaning ability.
Washing soda	To boost laundry cleaning	No reaction, but use assiduously	Washing soda (sodium carbonate) is an effective laundry booster at fighting stains and softening water. It can make Sal Suds more effective in extremely hard water. However, it does have a higher, more alkaline pH and could degrade fabrics more quickly. Try baking soda first, and do not use it on silks or wools.

So as I said, chemistry happens. If you have another substance you’d like to know if you can mix into Sal Suds, please ask me in the comments. I hope chemistry always happens in your favor.

What Can You Mix with Dr. Bronner’s Sal Suds?

What is Sal Suds

Further reading

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