I make lactobacillus fermented hot sauces and have noticed that they get a slight brownish discoloration over time. I'm curious if there is something I can do to keep the original color of the food.

  • Frame challenge: fermentation IS a preservation process on its own merit and food preservatives are there to prevent microbial growth (thus, preventing unwanted fermentation) Sep 1, 2021 at 7:30
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    Hi STW, the idea of "food color preservative" is so unusual, that at first it didn't even register with me, or with Juliana, what you are trying to do - at a first read, it seemed that you are asking for a preservative in the sense of making sure the food doesn't spoil. I reworded the question to get rid of the misleading phrase. It is also broader now, which is good - if there is a solution, it doesn't have to come in the form of a magic powder.
    – rumtscho
    Sep 1, 2021 at 8:52
  • Ok, now this reads better. More details are needed, tho: where do you observe the discoloration? All over the sauce or only at the surface? How do you process your ingredients - do you leave them whole or blend them before fermentation? What kind of vessel? Sep 1, 2021 at 12:47
  • I appreciate the attempt to remove ambiguity, but the edits lose the fundamental question of "what preservatives are compatible with lactic fermentation?"
    – STW
    Sep 14, 2021 at 23:43
  • @STW It seems that we still have a misunderstanding. "How do I preserve food (= prevent microorganisms from multiplying in it)" and "How do I solve the cosmetic problem of food changing its color" are two entirely different questions, addressed in different ways. Your text reads as if you think they are the same, making it impossible to answer. Please edit the text so it is clear which of the two questions you are asking, or tell us which one it is and let us edit it.
    – rumtscho
    Sep 15, 2021 at 8:06

1 Answer 1


If it's darkening that begins at the top, then I reckon it's oxidation. Get air bubbles out first (vibration, tapping) then pick a technique to remove air or replace with nitrogen. Freezing would also slow oxidation but not ideal for many textures.

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    If the issue is oxidation, then first ensure the brine completely covers the top of the veg, and introduce an air lock.
    – kitukwfyer
    Sep 12, 2021 at 22:44
  • Thanks for the answer, unfortunately my question was edited and made far broader than intended. The effects I observe are a general loss of color as well as darkening, which is usually most prevalent at the top. However I do use an airlock, and keep the vegetables submerged. Since inevitably small bits float above the brine I do occasionally stir things
    – STW
    Sep 14, 2021 at 23:47
  • @STW sorry it's been a million years, but whenever you stir your ferment, you're introducing oxygen. You might consider using a few thick slices of onion (or another veg that won't interfere with your hot sauce flavor profile) as a way to keep all the small bits of veg weighted down, and thus avoid the need to disturb/oxygenate it. You can also purchase fermentation weights for this purpose, but I'm happy to sacrifice an onion to the task personally. (Especially since I can eat the onion later!) Good luck!
    – kitukwfyer
    May 27, 2022 at 3:05

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