Sourdough Starter Smells Like Cheese

Sourdough starter can smell like cheese in the first couple of weeks as the bacteria grows and produces lactic acid that can smell cheesy. Over 50 types of bacteria have been found to grow in sourdough starter, and as they ferment many can produce distinctive smells. A common bacteria called Lactobacillus is often one of the first elements of a sourdough starter to start growing and it produces butyric acid which is what produces the cheese smell. Don’t worry, the Lactobacillus is what puts the sour in sourdough so it’s a good thing to have.

Lactobacillus is a probiotic (a “good” bacteria) that exists naturally in the human body and certain foods and multiplies in the presence of oxygen. As it multiplies, it breaks down the carbohydrates in the flour of the starter, a process that produces carbon dioxide. In addition to C02, the probiotics in the sourdough starter produce butyric acid which is often described as smelling like cheese. So don’t throw out that cheesy-smelling sourdough starter, it’s normal!

As the starter matures, the wild yeast will get stronger and grow, and the scents produced by the Lactobacillus and other bacteria will become more balanced. The Lactobacillus bacteria population will naturally decline and the cheesy smell will go away.

Should sourdough starter smell like blue cheese?

The blue cheese smell in sourdough starters is rare but completely acceptable for new sourdough starters. Many of the smells in sourdough starter are caused by naturally occurring bacteria that produce specific scents as they ferment and break down the carbohydrates in the flour. Two of the most common lactic acid bacteria found in sourdough starters, Lactobacillus plantarum and casei, are found in blue cheese and starters alike. While the blue cheese smell is actually the combination of dozens of contributing factors, such as mold and dozens of bacteria types, these L plantarum and L casei are considered contributors and are likely what is producing that blue cheese smell in your sourdough starter.

As the starter matures, the wild yeast and other bacteria will balance these out and the blue cheese smell will diminish. This can take 1-2 weeks, but just be patient and your starter will be fine.

Sourdough starter smells like parmesan

If your sourdough starter begins to smell like parmesan cheese this is perfectly normal in the early stages. Some of the lactic acid bacteria (LAB) in your sourdough starter produce butyric acid which is what produces that parmesan scent. For a new starter, the smell usually occurs between days 2-4 and can last up to a week.

Why does my starter look watery?

A young sourdough starter with a very strong parmesan cheese smell may also develop a layer of liquid that sits on top. This sourdough starter liquid is called the “hooch” and you have two easy options to deal with it:

  1. Pour it off (or use a spoon) to remove the hooch from your starter.
  2. Simply stir it into your starter.

The presence of hooch is more common with high-hydration sourdough starters and often occurs at the same time as the strong parmesan cheese smell.

What do I do if my sourdough starter smells like cheese?

If your sourdough starter smells strongly of cheese you can fix it by simply feeding your starter regularly (once or twice a day) for at least a week, or by replacing the water with pineapple juice.

Lactic acid bacteria that are found in sourdough starters can multiply easier at either a neutral or low pH level depending on the specific bacteria. If your sourdough starter has a high pH level then the bacteria will struggle with feeding and fermentation and this can cause the cheesy smell. By using pineapple juice with your sourdough starter you are introducing more acidity which causes the pH level to drop. As the pH level decreases due to the pineapple juice the bacteria become healthier and can ferment more easily and the smell should dissipate within a couple of days.

The pineapple juice method for sourdough bread

The pineapple juice method for sourdough starter is very effective in addressing the cheese smell in your starter, but simply waiting a few more days with regular feedings often fixes the issue as well. If you want to use pineapple juice in your starter simply replace the water in your feedings with the same volume of pineapple juice for two days, and then return to using water. It’s normal for the starter to give off a slightly fruity smell during this period.

If you don’t have any pineapple juice handy you can substitute it for orange juice without issue. Their pH levels are very similar and will help out your starter equally well.

Sourdough starter smells like sour milk

It is common for a sourdough starter to smell like sour milk in the first few days of creating a new batch of starter. Some folks report the dairy smell isn’t just sour but actually much worse, like rotten milk that’s been sitting in the hot sun for a few days. It can be completely rancid smelling and the good news is that you can absolutely recover your sourdough starter.

In most cases, simply keep feeding your starter 1-2 times a day for another week or two and the sour milk smell should dissipate. The smell is due to naturally occurring lactic acid bacteria that are fermenting in your sourdough starter and creating the undesirable smell. These bacteria will eventually be overpowered by the other bacteria that are developing as well as the wild yeast in your sourdough starter. There can be multiple types of yeast present in your starter and over 50 types of bacteria. That’s quite a microbial colony living in your sourdough starter and the bad smell is usually because one type of bacteria is multiplying much more than the others and its smell become dominant. However, over time the bacteria and yeast in your sourdough starter will balance out and the rancid smells will go away.

More fixes for your sourdough starter that smells like cheese or sour milk

If the smell isn’t going away after two weeks of regular feedings and you’ve even tried the pineapple juice method then more drastic action may be required. Follow these tips to make sure you’re doing everything you can to save your starter:

  • Transfer your starter to a clean, glass container.
  • Ensure you only ever use clean spoons or spatulas to feed and mix your sourdough starter.
  • Avoid temperatures above 90°F or 32°C.
    • Warmer temperatures encourage microbial growth however if it’s too hot the wrong types of bacteria may overpopulate your starter’s colony.
  • If your starter is more than two weeks old, consider feeding it more often (going to twice a day instead of just once for example) as the smell may indicate that the bacteria are overly hungry.

Finally, if you’ve tried all of the above it may be time to simply toss your starter and try again with a new one. Be sure to check out other common smells for sourdough starter.

1 thought on “Sourdough Starter Smells Like Cheese”

  1. My sourdough starter is about 3 years old now. It’s been doing fine but about 3 months ago I said it and it container on my counter and forgot about it. I generally keep it at a 50/50 concentration level so it’s rather moist. However, I don’t know if you have ever smelled raclette cheese but, it is likely the worst smelling stuff on earth. That smell started coming from my sourdough starter. I open the container the jar was in and visually it looks fine. It’s very gray on top with hooch and beneath it the starter looks beautiful. However, The smell of raclette is monstrous. I permeates everything in his just nasty. What type of bacteria cause that? I’m hoping that some of your tips here will help to alleviate the stench.


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