The Unsafe Container Too Many People Store Their Sourdough Bread Starters In

Making sourdough bread at home can be an incredibly fulfilling experience despite the many ways the process can be challenging. While temperature-related mistakes for sourdough are well-documented and thus easier to avoid, fewer people know the do's and don'ts of how to properly store a sourdough starter. We discussed the storage of bread starters with Erik Fabian, the co-founder of Sourhouse and an expert on all things sourdough. He says there's a type of container that could negatively impact your dough's flavor and potentially even make it unsafe to consume.

"Generally avoid aluminum containers for sourdough because the acid can react with the metal and get in the dough," Fabian explains. When metal leaches into the dough, there's a risk of metal toxicity, so it's best to avoid it. Plus, even if your sourdough starter doesn't retain a lot of the metal from the storage container, it can still produce a metallic taste that completely throws off the bread's flavor. Considering that sourdough's unique flavor is what truly sets it apart from other breads, even just a slight hint of metal can completely disrupt your final loaf's quality.

Now, while you should avoid putting your sourdough starter in aluminium containers in most situations, not every metal is dangerous to the acidic substance. Erik Fabian says, "Stainless steel is generally fine for mixing a batch of dough." However, that isn't to say stainless steel is the best option. "The ideal jar is a glass jar," Fabian reveals, "with straight sides so it is easy to watch the starter rise and clean. A lid made of a solid material will minimize bad microbes that can make your starter sick." 

While this may seem obvious to those who have noticed that most great sourdough starter kits on the market include a glass jar for storing the dough, the usefulness of a plain glass jar can't be ignored. Not only are they non-reactive and thus won't impact your sourdough's flavor, but they are also easy to clean and completely transparent, making them great for keeping track of your starter's progress over time.

Nevertheless, if you are going to stray from glass jars for the job, there are a few other types of containers that shouldn't be used. "I personally avoid plastics for long-term starter storage to minimize microplastics in my food," Fabian adds, before also advising that bakers should "avoid cloth lids as they tend to encourage the growth of other microbes that can infect your starter."