Understanding how to make sourdough in hot and humid weather can be a challenge - but one that is easily overcome when armed with the right knowledge.
Living in Australia, I deal with hot and humid weather a lot (as well as freezing cold temps too - we really do have it all!).
After being asked many times about how humidity affects sourdough, I thought I would put together this guide on how to make sourdough in hot and humid weather so that I could share this knowledge with anyone that may need it.
In summary, when baking sourdough in high heat and humidity, you need to:
- Use cold water (or even ice) in your sourdough starter and dough
- Use smaller amounts of sourdough starter to increase bulk ferment time
- Feed your sourdough starter often to keep it mild and healthy
- Monitor dough temperature
- Use the fridge to reduce dough temp if needed
- Monitor work surface and equipment temperatures
- Reduce hydration of your recipe if very humid
- Increase salt percentage
- Avoid ingredient additions that increase moisture (like cheese, fruits, vegetables, pickles etc)
How Does High Humidity Affect Sourdough?
Sourdough ferments best at humidity levels between 60 and 80%. If you are outside of this (ie at high altitude in a dry climate) or above this in a hot and very humid environment, you may run into some challenges.
High humidity affects sourdough in the following ways:
- Increases amount of water absorbed by the dough
- Decreases the time it takes to bulk ferment
- Increases condensation and moisture during cold fermentation
You can see how you might end up with a wet and sticky mess if you don't make some adjustments, right?
Why Is It Hard To Bake Sourdough Bread In Hot & Humid Weather?
Sourdough is more difficult to bake in hot and humid weather because:
- Increased moisture can increase hydration and make the dough feel wetter and slacker than normal.
- Reduced bulk fermentation time makes it much easier to over ferment the dough.
- Slacker, wetter dough is more difficult to shape.
- Increased humidity can encourage mold to form on bannetons.
Sourdough can be finicky at the best of times, but add in some extra moisture and you might just have a disaster on your hands!
Best Tips for Making Sourdough In Hot & Humid Weather
There are lots of things that you can do to ensure you have sourdough success, even when it's really hot and humid!
I've put together a list of things you can do to minimise the effect of heat and humidity on your dough and tried to explain each one in full.
Use Cold Water or Ice
One of the easiest ways to combat humidity when baking sourdough is to use ice cold water in both your sourdough starter and your dough. Cold water from the fridge immediately cools the temperature of your dough and slows down the fermentation process.
If it's really hot and humid, you could even use ice in your dough, however I find cold water from the fridge is enough.
If I'm fermenting dough overnight (yes I still do this even in the summer), I will use ice cold water to mix the dough and then I will leave it in the laundry room on the cool tiled floor to ferment. It's all about using what you have to your advantage!
Use Smaller Amounts of Sourdough Starter
Reducing the amount of sourdough starter in your dough will reduce the risk of over fermentation in hot and humid weather. If you're already using my sourdough recipe, you'll know that I use just 50g of starter, which is already less than other sourdough bakers.
But if it's really warm and humid, I reduce this even more! Especially if I'm bulk fermenting overnight or want a really long fermented sourdough bread.
You can use as little as 10g of starter to get the job done.
Monitor Dough Temperature & Use Your Fridge
Monitoring dough temperature is a good way to gauge fermentation. You can use a food thermometer like this one.
While I don't think it's necessary to check dough temp in normal circumstances, if it is really hot and humid where you live, using a thermometer may prevent your dough from over proofing and ending up with a wet and sticky mess!
You don't want your dough to be climbing too much above 80F (26C) as this will speed up bulk fermentation too much.
The best thing to do is experiment and see what the best temperature for your dough is, rather than be bound by a strict guide.
If the dough temp is soaring too high, throw it in the fridge for a little while. You don't want to start the cold ferment, you just want to bring the temp of your dough down a bit to slow fermentation.
Monitor Work Surface & Equipment Temperatures
When the weather is hot and humid, keep an eye on the temperature of your work surface and equipment like bowls. I don't necessarily take temperatures, but if something feels too warm then it probably is!
Now warm surfaces and equipment is not the end of the world, but when you add in the humidity factor, it can make a big difference!
So utilise marble or stone boards for working dough as they stay cooler. Run bowls and spoons under cold water to keep them cool or just pop them in the fridge or freezer for a bit (making sure you dry them thoroughly to avoid even more moisture in your dough).
Since humidity causes increased moisture in the air, decreasing the hydration or moisture in your sourdough recipe is an easy way to combat it.
When the air is humid your dough will absorb more water from the air around it. When this added to the water that's already in your dough, this increased hydration can wreak havoc on your dough.
Reduce the water in your sourdough recipe to ensure that you don't end up with a wet, sticky mess.
Reducing the hydration of your recipe is also a good idea because higher hydration dough ferments faster and this, combined with hot and humid weather, will result in dough that over ferments too quickly.
You can read my sourdough hydration for beginners guide here.
Increase Salt Percentage
Salt hampers fermentation. So the more salt you use, the more it will hamper the fermentation of your dough.
Most sourdough recipes contain 2% salt - so for 500g of flour you'd add 12g of salt (give or take a little for your own taste). If you're new to baker's percentages, this article will explain what you need to know.
In humid weather you could increase this percentage to 3 or even 4% to slow down fermentation.
You can read more about the effects of salt on sourdough here.
Keep The Dough Clean & Lean
When baking sourdough in hot and humid weather my advice is to keep the dough lean and clean. Until you are really comfortable with the changes you need to make in hot and humid weather, just stick to flour, water and salt.
Adding extra ingredients like sugar, honey, oil or even cheese can speed up fermentation and this makes it even more difficult to handle your dough in humid weather.
Once you've got a bunch of successful sourdough loaves under your belt, you can experiment with these extra ingredients.
Does High Humidity Affect Sourdough Starter?
Yes high humidity does affect sourdough starter because it will increase the amount of water in the starter, as well as encourage condensation.
High humidity can cause your starter to be runnier than it should be, so feeding it a higher ratio of flour can be beneficial. Sourdough starter maintained in hot and humid conditions will consume flour and water more rapidly and be past its peak and often too runny to use.
Feeding the starter with more flour than water can combat this and ensure your sourdough starter it's always ready to use. Ice water is also really handy to slow your starter down.
If your starter is mature enough, storing it in the fridge is also an option.
You will also need to be mindful of mold in hot and humid conditions. Extra condensation inside your jar can encourage mold to form which would mean having to toss your starter and begin again from scratch.
Using Bannetons in High Humidity
When you are living in a hot and humid climate, using and storing rattan bannetons can be problematic because high moisture levels in the air cause the bannetons to mold.
I mostly recommend rattan bannetons that wick away moisture as they are very effective, however if you are living in a high humidity area, a plastic banneton is a better option.
To stop rattan bannetons from molding after use, follow these steps:
- always bang out excess flour and allow to dry in a well ventilated area.
- store the clean, dry banneton in a well ventilated area and never place in a plastic bag.
- never run the banneton under water to clean as this encourages mold growth in humid environments.
You can read more about maintaining bannetons here.