Soylent going funky by the end of the day


Hi all.

I mix my soylent in the mornings in a blender, taking about 3/4 with me to work in a bottle and leaving the remainder in the fridge for the evening. I typically finish what I take with me before I get home. I’ve noticed that if I leave dregs of Soylent in the shake bottle until late evening (or worse still, the next morning!) it will smell very pungent and unappetising, a bit like fruit left in a hot place to ferment.

Has anyone else experienced anything similar? Any suggestions how to avoid this would be great as I’d rather not be encouraging bacterial/microbial growth my drinking vessels if at all possible.

One thought I had was use of standard food preservatives. There is a short list here which includes compounds containing Potassium and Sulphur. Perhaps these could both maintain freshness and also count towards our mineral intake?
I think it should be possible to find something along these lines in brewing shops (which I recall Rob saying he used as an ingredient source).


Them’s fightin words, boy!


I have the same problem but worse. I live in a place that has 24/7 30 celsius at least during summer. I always keep it in the fridge, if it stays out for more than 5 hours, its gone.
Even when I take out a small amount, I add a ton of ice cubes to keep it cold…but I fail quite often :stuck_out_tongue:


Problem with using sulfites is that some people are allergic or sensitive to them… A lot of dried fruit uses it as a preservative, and some wine has it as well, and my mate isn’t able to have either.


I can’t say I am experiencing the same issue with my blend, and I have a bottle sitting out on my desk for 8+ hours every day. Would you mind posting your recipe? Perhaps there’s something in it that’s causing “the funk”.


Yeah I was going to post it up for consideration, I forgot. I wonder actually if it might be my Spirulina alage coming back to life after being rehydrated!! I will try a day without them and see what happens. Will post the rest of the recipe when I get home, though it’s fairly typical stuff on the whole.

Edit: here is everything that has been going in my mix.
Palatinose, Powdered Oats, Whey Protein, Soy Protein Isolate, Cocoa Powder, Tummy Fiber (acacia), Milk, Olive Oil, Sunflower oil, “Omega 3 Liquid” (fish oil), Creatine, Blueberry Extract, Spirulina, MSM, Phosphatidyl Serine, Inositol, Dipotassium Phosphate, Sodium Chloride, Iodine Tincture, Vitamin C, Rhodiola Rosea.

Most of the unusual things are in very small quantities. Full details here:
Today I bought some “wine stabiliser” which contains sodium metabisulphite and potassium sorbate in an unstated ratio. Tomorrow, I will try it!



I also add 20g honey and 2 omega 3 softgels

and soak the oats for an hour before the mixing

right now room temp is 32 celsius


sogviper, adding probiotics is bound to make it go funny quicker. Your spreadsheet is rammed full of info but I’m really struggling to figure it out. How much vanilla flavouring do you use? Also I think you don’t need to worry about flouride, just brushing your teeth probably gets you enough. The RDI is tiny!


I noticed you have Milk in your recipe… If it’s constantly hot, it’s no wonder it goes bad.


just 0,2 grams of some organic dark brown vanilla. Bourbon vanilla.

I’m aware of the flouride thing but I brush my teeth with baking soda only :stuck_out_tongue:
maybe I could switch to something more commercial eventually…

I know, my sheet is pretty messy, just stay focused on the ‘form’ and ‘amount per day’ lists.
and don’t even try opening that with excel. I made it on libre office…it’s not MS friendly at all!


Really? Why do you do that?


The feel is better afterwards. I can tell (intuitively) that my mouth feels better with the higher ph effect of brushing with soda. I also happen to use soda for taking showers (along with apple vinegar for hair), so its cheaper and fills 2 roles which is great if you move around a lot with a backpack :slight_smile:


If you cover it soylent should last for a few days in the fridge and at least a full day outside of one. However, if you leave some out and warm it will spoil pretty quickly since it is so packed with nutrients.

Official Soylent has no preservatives but I do not think they are unsafe in the quantities typically used. Take a look at Potassium Sorbate. Beware of Benzoic Acid though, there is some evidence it can react with ascorbic acid (Vitamin C) and form benzene.

I get my more exotic food additives from Alibaba. They will usually send you a sample for free, and only a few mg are required.


Cheers for the input Rob, though to clarify I was talking about my own custom soylent, not your recipe. Can I ask why in particular you recommend Potassium Sorbate? I notice it’s very cheap on ebay so will probably try it out.

Yesterday I tried a “Wine Stabiliser” product sold by Wilkinsons in the UK which contains Sodium Metabisulphite and Potassium Sorbate in unspecified amounts (grr!). I used 50mg to approximately 1.5 litres of Soylent, and the next morning my unwashed shake bottle is definitely still a little off, though maybe not as bad as before. I’m reluctant to up the dose as the Acceptable Daily Intake of Sodium Metabisulphite is only 0.7mg/kg. That said, the instructions suggest 1g in a gallon of wine, though I’m assuming they don’t consider that the wine may be your sole food and nutrient source!


Preservatives have different mechanisms of action and since soylent allows for different kinds of growth it may need a few different kinds i.e. anti-mold and anti-bacterial.

I’m not sure if they presumed one would drink the whole gallon in a day! Good to err on the side of safety here, though the ADI of Potassium Sorbate is much higher, at 12.5mg/kg.

Another thing I’m wanting to try is sterilizing with UV light.


Doesn’t that run the risk of killing nutrients? I know a lot of them are damaged by light in general, and the intense UV would have to be worse on them…


I agree. I assume @rob will do the necessary research but it does seem a bit unlikely to work.