Fermentation is a mix of science and art. While it’s easy to follow a recipe and use precise measurements there are many other factors that can influence the outcome. Often it’s these subtle variations in flavor are one of the foodie joys of eating fermented foods!
A few of the less controllable factors in fermenting include:
- variations in the fermenting culture
- indoor air-quality and wild cultures
- temperature and humidity
This post is part of a series of posts on fermentation problems and solutions. Other topics include:
One of the common concerns is what to do if there are no signs of fermentation after 24 to 48 hours.
It doesn’t matter whether your sourdough never bubbles, yogurt doesn’t set, or the airlock in your wine isn’t bubbling, the causes are usually similar.
Here’s an overview of the most common reasons why there might be no signs of fermentation, and what you can do about it.
Probably the most common reason why people are concerned about the lack of fermentation is because of their expectations.
Not all ferments actively bubble. And sometimes the photos that accompany a recipe aren’t accurate. While I only ever use photographs that I took myself, there are a surprising number of food bloggers who use stock photos.
Here are a few types of ferments that might not meet your expectations:
- Gluten-free sourdough is usually not as bubbly as regular sourdough. The size of the bubbles will also depend on the type of flour mix used.
- Ferments that use apple cider vinegar as a culture don’t bubble like salt-brined ferments.
- Most store-bought dairy products contain thickeners and other additives. So homemade sour cream, milk kefir, and yogurt won’t be the same as store-bought.
It takes time to ferment, particularly if it’s your first time making a particular type of ferment. So give your recipes the time required to get going. Sometimes it can take up to a week really start bubbling.
This is particularly true for wild-culture-based ferments. Even if you start with a store-bought culture, the wild culture in your home matters more. So if it’s your first time making sourdough, ginger bug, or tepache, then expect it to take 5 to 10 days to start fermenting actively. See the section below on indoor air quality for more information.
The health and vigor of your culture will really impact how quickly your ferment starts.
- The most common cause of culture death is accidentally cooking it. Don’t stir your yogurt culture into milk that is hotter than 110F (40 C). Don’t add yeast to your beer or wine before it cools to 70F (21C).
- A culture needs to be fed regularly to be healthy and vigorous.
Using heavily chlorinated water can prevent fermentation. The goal of chlorinating water is to provide safe drinking water by killing all the bacteria and other pathogens.
Unfortunately, simply passing your water through a charcoal filter isn’t always the best way to filter it. Here’s a whole post on filtering water for fermentation.
Many ferments rely on the wild yeasts and bacteria that live in your house. Here are a few reasons why your home might not contain the right cultures for fermenting:
- If you are a newbie fermenter, then your house might not have a lot of the right strains of yeast and bacteria, so you may struggle to get your ferments to colonize. Keep fermenting! It will slowly change the makeup of wild cultures in your home and you’ll find that it will become easier and easier to kick start a ferment.
- It’s harder to catch a wild culture in heavily polluted cities.
- Hepe (or similar) air filtration systems will remove all wild yeasts and bacteria.
- Anti-bacterial cleaning supplies also kill wild fermentation cultures.
- Mold issues in the walls and ceilings of a home can contaminate ferments. To prevent mold, stick with ferments that can be made in a fido jar or capped with an airlock.
Most ferments have an ideal temperature range. Anything outside of this range will slow down or stop the ferment. While it’s not always possible to maintain the right temperature, just do your best.
- Keep ferments warm by placing them on top of your fridge or next to your water heater.
- Keep ferments cool in a dark closet, garage, or cellar.