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Fermented hot sauces

Chilies, salt and a few weeks, then the blender. How to ferment the mash, why the pH that counts is the finished sauce's, and how to bottle it.

8 min read Getting good Reviewed October 26, 2026 39 facts, each with its source

What a fermented hot sauce is

It's made in two stages. First, the chilies are ground with their salt and ferment for a few weeks, like sauerkraut. Then everything is blended into a sauce, bottled and kept in the fridge.

Salt alone isn't enough to stop the botulism bacterium, but it lets the lactic acid bacteria work faster and bring the pH down1. And a bottled sauce is exactly what that bacterium needs to make its toxin: no air, a pH above 4.6, a temperature above the fridge's and plenty of water2. That's why two things rule here: the pH and the fridge. Ideally, the ferment gets below 4.6 as fast as possible3.

Hot sauces need a pH reading, ideally with a meter rather than strips: in a red mash, strips are hard to read.

The chilies and what goes with them

Any chili works: jalapeño, serrano, habanero, cayenne or bird's eye. Wash them with water, without scrubbing, so you don't remove the good bacteria4, and pull off the stems. Wear disposable gloves: they protect your hands and eyes from the chili5.

Onion, garlic, ginger, carrot or fruit go in from the start, chopped with the chilies, and ferment with them. That way they share the salt and the acidity. Garlic goes in as an aromatic, in small amounts: it's never the base of the sauce, because there are no validated recipes for fermenting it6.

Salt: 25 g per kilo

Weigh everything together, stems already off: chilies and aromatics. The salt goes on that weight. Fervida uses 2.5%: 25 g per kilo7.

Chilies and aromatics Salt at 2.5%
500 g 12.5 g
800 g 20 g
1 kg 25 g

The minimum is 2%, and that's a house rule: reducing the salt in a vegetable ferment is not safe8. Up to 5% there's no warning. More doesn't help either: with too much salt it won't ferment and the pH won't drop9. Always weigh it, and use salt without additives, such as canning salt10.

Packing and fermenting

Grind or chop the chilies with the salt into a coarse mash. The salt draws out the liquid. Pack it into a glass jar, never a metal one, which reacts with lactic acid11, and press it down until the liquid covers it. Add a weight: everything has to stay under the liquid12, because mold needs oxygen13. Leave headspace: it rises in the first days.

Close it with a valve lid, which lets the gas out14, or a regular lid you loosen now and then15, only briefly16. Keep it in the dark, because lactic acid bacteria are sensitive to light17.

Temperature What happens
Below 16 °C (60 °F) It won't ferment
16–20 °C (60–68 °F) 5 to 6 weeks18
20–22 °C (68–72 °F) Ideal: 3 to 4 weeks
22–25 °C (72–77 °F) 3 to 4 weeks
Above 25 °C (77 °F) It over-ferments and can spoil19

Between 22 and 25 °C (72 and 77 °F) no source gives times: Fervida uses those of the 20–22 °C (68–72 °F) band, and that's a house rule.

It's ready when it stops bubbling and the pH is 4.6 or below20. If it has stopped bubbling but the pH is still above, give it longer and check every one or two days21.

The finish: the pH that counts

Blend the mash with all its liquid. The finished sauce has to be below pH 4.622, and in practice you aim for 4.2 or below23. That pH is measured once the whole mix has the same acidity: it's the equilibrium pH24. If you add anything, wait for the sauce to even out before measuring.

Vinegar is the only thing that lowers the pH. SDSU, South Dakota State University Extension, calls for adding an acid such as vinegar to make sure it's below 4.625. Use store-bought vinegar: homemade vinegar has an acidity nobody knows26.

Everything else raises it. Fruit, garlic, onion or water added raw at the end raise the pH without you noticing: a ripe mango is between 3.40 and 4.8027. Without a pH reading, they don't go in: that's a house rule. If you want fruit, add it at the start, with the chilies, and count its weight for the salt.

Bottling and storing

SDSU also recommends bringing the sauce to a boil28, because pH alone won't kill any pathogens that may be present29. Boiling also kills the lactic acid bacteria30 and stops the fermentation, so the bottles don't build pressure. If you don't boil it, it keeps fermenting slowly: bottles of a commercial sriracha have been recalled because they bloated and could burst when opened31.

Boiled or not, the sauce always goes in the fridge, which stops the fermentation: vegetable ferments keep there for up to 9 months32. If it has fruit or anything raw added at the end and you didn't boil it, Fervida counts one month. Both are house rules: outside the fridge you'd need a controlled pH and a heat treatment that can't be checked at home.

Never in oil, neither a mash topped with oil nor the sauce. BfR, the German Federal Institute for Risk Assessment, advises against making and storing vegetables or herbs in oil at home33.

What can go wrong

What you see What it is What to do
A smooth white film Usually kahm yeast34 Remove it and check the pH: it shouldn't go above 4.635
Fuzz or green, blue, brown or black spots Mold36 Throw out the whole batch37: it can't be scooped out38
A putrid smell A failed fermentation39 Throw it out
The pH won't drop below 4.6 Too little salt, too cold, or a mash that never got going Keep measuring; don't blend or bottle it like this
A bulging bottle It's still fermenting Open it cold, over the sink; if you didn't measure the pH, throw it out

The recipes and your own

  • Fermented jalapeño hot sauce: green, with onion and garlic. The one to start with.
  • Homemade sriracha: red chili and garlic, thick, boiled before bottling.
  • Tabasco-style hot sauce: chili, salt and vinegar, with weeks of rest in the fridge.
  • Habanero mango hot sauce: the mango ferments with the chilies from day one.
  • Fermented harissa: a chili and pepper paste with caraway, without oil.
  • Tomatillo and serrano salsa verde: tangy and thinner.

To make your own with what you have, use "What can I ferment with what I have?". You choose the chili and the extras, and it gives you the weighed salt and the times. The extras weigh at most 30% of the chilies: that's a house rule, so it's still a chili sauce.

Where every number comes from

Every number in the text leads to its figure: the exact sentence from the official guide it comes from, in its own language.

  1. 1

    Salt alone doesn't stop botulism, but it speeds up the acid

    “The salt addition isn't enough to prevent C. bot from growing, but it lets the good guys work faster and produce acid to get the pH down.”

    Ask Extension (Oregon State University; expert answer by Joy Waite-Cusic) · Should botulism bacteria be a concern making fermented hot sauce? (#815501, 2022) · read on October 25, 2026

  2. 2

    Botulism needs: no air, pH above 4.6, out of the fridge and plenty of water

    “Clostridium botulinum can form a deadly toxin under very specific conditions (anaerobic conditions, pH >4.6, temperatures above refrigeration, and high water activity).”

    Ask Extension (Oregon State University; expert answer by Joy Waite-Cusic) · Should botulism bacteria be a concern making fermented hot sauce? (#815501, 2022) · read on October 25, 2026

  3. 3

    Ideally, get below 4.6 as fast as possible

    “Ideally (for food safety purposes), a food fermentation would get the pH of the system below 4.6 as fast as possible.”

    Ask Extension (Oregon State University; expert answer by Joy Waite-Cusic) · Should botulism bacteria be a concern making fermented hot sauce? (#815501, 2022) · read on October 25, 2026

  4. 4

    Wash without scrubbing, to keep the good bacteria

    “Do not scrub the produce, as you may remove the good bacteria needed for fermentation.”

    University of Minnesota Extension · Preserving food at home: Fermentation (reviewed 2026) · read on October 25, 2026

  5. 5

    Disposable gloves for the chilies

    “Disposable food handler gloves (highly recommended) for protection from red pepper powder”

    Colorado State University Extension · Understanding and Making Kimchi (2025) · read on October 20, 2026

  6. 6

    There are no validated recipes for fermenting garlic

    “There are currently no validated recipes for fermenting garlic.”

    Ask Extension (Loretta Sweeney, Franklin County, Ohio) · Food preservation and safety: lacto-fermenting garlic #930666 (2026) · read on October 25, 2026

  7. 7

    25 g of salt per kilo, 2.5%

    “2.5% 25 g / kg food”

    UC Master Food Preservers, Inyo-Mono · Brine Math Made Easy · read on October 20, 2026

  8. 8

    Reducing salt is not safe

    “It is unsafe to reduce salt in lactofermented vegetables.”

    UC Master Food Preservers, Inyo-Mono · Brine Math Made Easy · read on October 20, 2026

  9. 9

    With too much salt it won't ferment and the pH won't drop

    “If there is too much salt in the brine, fermentation will not occur and the pH will not drop to become more acidic.”

    University of Minnesota Extension · Preserving food at home: Fermentation (reviewed 2026) · read on October 25, 2026

  10. 10

    Salt without additives, such as canning salt

    “The salt used in fermentation should contain no additives. Canning or pickling salt is recommended”

    University of Illinois Extension · Fermentation handout (2020) · read on October 20, 2026

  11. 11

    No metal: it reacts with lactic acid

    “Avoid metal containers as the metal will react with the lactic acid that the bacteria produce.”

    University of Minnesota Extension · Preserving food at home: Fermentation (reviewed 2026) · read on October 25, 2026

  12. 12

    Everything under the liquid

    “All produce should be submerged in the brine liquid.”

    UC Davis, Department of Food Science and Technology · Common issues with fermented fruits and vegetables (v1.0, 15-mar-2022) · read on October 20, 2026

  13. 13

    Mold needs oxygen

    “Molds require oxygen to grow.”

    UC Davis, Department of Food Science and Technology · Common issues with fermented fruits and vegetables (v1.0, 15-mar-2022) · read on October 20, 2026

  14. 14

    The valve lets the gas out

    “it is important to vent the jar with a one-way valve to release the gases that form during fermentation.”

    K-State Research and Extension (Kansas State University) · Taking a New Look at Fermented Foods (MF3491, June 2020) · read on October 20, 2026

  15. 15

    Without a valve, loosen the lid now and then

    “If a one-way valve is not used, the gases will need to be released manually by loosening the lid occasionally.”

    K-State Research and Extension (Kansas State University) · Taking a New Look at Fermented Foods (MF3491, June 2020) · read on October 20, 2026

  16. 16

    The lid is opened only briefly

    “The lid should only be opened briefly to limit oxygen from entering the container.”

    University of Minnesota Extension · Preserving food at home: Fermentation (reviewed 2026) · read on October 25, 2026

  17. 17

    In the dark: lactic acid bacteria are sensitive to light

    “Containers with fermenting produce should be stored in a dark place, as Lactobacillus are sensitive to light.”

    University of Minnesota Extension · Preserving food at home: Fermentation (reviewed 2026) · read on October 25, 2026

  18. 18

    3 to 4 weeks; 5 to 6 below 68 °F

    “Allow your product to ferment for 3 to 4 weeks. If temperatures are below 68 degrees Fahrenheit, fermentation may take 5 to 6 weeks.”

    University of Minnesota Extension · Preserving food at home: Fermentation (reviewed 2026) · read on October 25, 2026

  19. 19

    Ideally 68 to 72 °F; above 78 °F it spoils; below 60 °F it won't ferment

    “A temperature between 68 and 72 degrees Fahrenheit is ideal. Temperatures over 78 degrees Fahrenheit can cause over fermentation and spoilage. Temperatures below 60 degrees Fahrenheit will inhibit fermentation.”

    University of Minnesota Extension · Preserving food at home: Fermentation (reviewed 2026) · read on October 25, 2026

  20. 20

    Ready at pH 4.6 or below with no bubbles

    “When a pH of 4.60 or lower is reached and bubbling has stopped, the ferment is ready.”

    University of Minnesota Extension · Preserving food at home: Fermentation (reviewed 2026) · read on October 25, 2026

  21. 21

    No bubbles but above 4.6: keep going and check every 1 to 2 days

    “If bubbling has stopped but the pH is still above 4.60, continue to ferment and check the pH every 1 to 2 days.”

    University of Minnesota Extension · Preserving food at home: Fermentation (reviewed 2026) · read on October 25, 2026

  22. 22

    Hot sauce, below pH 4.6

    “When making a hot sauce, the pH must be less than 4.6.”

    SDSU Extension (South Dakota State University) · How to Make a Safe Hot Sauce (updated October 2023) · read on October 25, 2026

  23. 23

    In practice, 4.2 or below

    “but in practice this value is usually 4.2 or below for safety reasons.”

    Cornell Food Venture Center (Cornell AgriTech) · Acid & Acidified Foods · read on October 25, 2026

  24. 24

    Equilibrium pH: once the whole mix has the same acidity

    “Equilibrium pH means the final pH measured in the acidified food after all the components of the food have achieved the same acidity.”

    Cornell Food Venture Center (Cornell AgriTech) · Acid & Acidified Foods · read on October 25, 2026

  25. 25

    An acid such as vinegar makes sure it's below 4.6

    “an acid, such as vinegar, should be added to ensure that the pH is below 4.6”

    SDSU Extension (South Dakota State University) · How to Make a Safe Hot Sauce (updated October 2023) · read on October 25, 2026

  26. 26

    Homemade vinegar isn't used for pickling

    “Do not use homemade vinegar when pickling. The acidity of homemade vinegar is not consistent.”

    Penn State Extension · Advice about Vinegar (updated July 2026) · read on October 25, 2026

  27. 27

    A ripe mango, pH 3.40 to 4.80

    “Mangoes, ripe 3.40 - 4.80”

    U.S. FDA, CFSAN (copy hosted by RiverStone Health, Yellowstone County public health department) · Approximate pH of Foods and Food Products (April 2007) · read on October 25, 2026

  28. 28

    Hot sauces should be brought to a boil

    “Additionally, hot sauces should be brought to a boil.”

    SDSU Extension (South Dakota State University) · How to Make a Safe Hot Sauce (updated October 2023) · read on October 25, 2026

  29. 29

    pH alone doesn't kill pathogens

    “as the pH alone would not control growth of pathogens or kill any pathogens that would be present”

    SDSU Extension (South Dakota State University) · How to Make a Safe Hot Sauce (updated October 2023) · read on October 25, 2026

  30. 30

    Heat kills the lactic acid bacteria

    “However, the high temperatures of canning will kill any beneficial Lactobacillus bacteria.”

    University of Minnesota Extension · Preserving food at home: Fermentation (reviewed 2026) · read on October 25, 2026

  31. 31

    Pressure can make bottles burst when opened

    “The build-up of pressure in the bottles may cause them to explode upon opening.”

    Singapore Food Agency · Recall of “Huy Fong Sriracha Hot Chilli Sauce” (media release, 27 December 2019, updated) · read on October 25, 2026

  32. 32

    The fridge stops fermentation; up to 9 months

    “Refrigeration stops the fermentation process. Fermented produce can be kept refrigerated for up to 9 months.”

    University of Minnesota Extension · Preserving food at home: Fermentation (reviewed 2026) · read on October 25, 2026

  33. 33

    BfR advises against storing homemade foods in oil

    “Das BfR rät daher davon ab, selbst erzeugte Produkte wie Gemüse in Öl oder Kräuter in Öl im Privathaushalt auf Vorrat zu produzieren und zu lagern.”

    Bundesinstitut für Risikobewertung (BfR) · Selbst hergestellte Kräuteröle und in Öl eingelegtes Gemüse bergen gesundheitliche Risiken (Mitteilung Nr. 001/2016) · read on October 25, 2026

  34. 34

    The white film is usually kahm yeast

    “This film is typically yeast, often referred to by home fermenters as Kahm yeast.”

    UC Davis, Department of Food Science and Technology · Common issues with fermented fruits and vegetables (v1.0, 15-mar-2022) · read on October 20, 2026

  35. 35

    pH should not go above 4.6

    “The pH can be checked periodically to ensure it does not rise above 4.6.”

    UC Davis, Department of Food Science and Technology · Common issues with fermented fruits and vegetables (v1.0, 15-mar-2022) · read on October 20, 2026

  36. 36

    Mold is usually green, blue, brown or black

    “Mold is typically green, blue, brown, or black in color.”

    UC Davis, Department of Food Science and Technology · Common issues with fermented fruits and vegetables (v1.0, 15-mar-2022) · read on October 20, 2026

  37. 37

    If there's mold, the whole batch goes

    “If you confirm mold growth on any part of a ferment, it should be immediately discarded.”

    UC Davis, Department of Food Science and Technology · Common issues with fermented fruits and vegetables (v1.0, 15-mar-2022) · read on October 20, 2026

  38. 38

    Mold can't be scooped out

    “The mold cannot be scooped out, as the roots will still be in your food and could make you sick.”

    Ask Extension (Clackamas County Extension, Oregon State University) · Pickle/olive brine surface mold spots #889210 · read on October 20, 2026

  39. 39

    A putrid smell is a failed ferment

    “A putrid smell indicates a failed fermentation.”

    UC Davis, Department of Food Science and Technology · Common issues with fermented fruits and vegetables (v1.0, 15-mar-2022) · read on October 20, 2026

Keep reading

pH and why it matters most pH meters and strips Salt: how much and why Fermenting safely: botulism and how to avoid it Jars and lids The complete guide to sauerkraut Fruit in a ferment: sugar, yeast and alcohol Cooking with ferments