I am very new to sourdough baking and gaining an interest in the subject so please forgive what may seem like newbie question.

I have two starters on the go at the moment. The first starter came as part of a "sourdough kit" which I was given as a present. It seems to be quite mature off the bat and has a somewhat 'yeasty' smell.

The second starter I got going from scratch. Just flour, water, a jam-jar and my daughters heat pad from the snake tank. (The snake died so the heat pad was going spare). I am running the heat pad at about 25 degrees celcius. Both starters are being fed daily and stored on the pad. The second starter has a more sour smell - almost stomach-acid in aroma.

Both have similar properties - they bubble up in the same way although the second starter has patches where the bubbles are a lot smaller. The second starter started life in a small plastic cup and was transferred to a jam-jar as it grew.

So I am wondering what is 'normal'. The 'stomach-acid' smell or the 'yeasty' smell? Or is there variations on what is considered normal?

Feeding at the moment is morning and night with about 70g/70ml flour/water.

3 Answers 3


One is on the heat pad and the other is...where? Different temps will facilitate the growth of different yeast and bacteria. Also, your kit is likely populated with different micro flora than the starter you created. Finally, which "smell" would you rather use to bake bread? I would go with yeasty. Starters get acidic fairly quickly. This inhibits the growth of micro flora. That is why feeding requires you to remove a significant amount before replenishing. If you want to play, remove most of the "stomach-acid" starter, and feed the rest with flour and water (maybe remove it from the heating pad as an experiment...or try two small versions...on on and one off). Build up again, and see if you can achieve a more pleasant aroma.

  • 1
    Thanks for the response. They are both being cultivated on the heat pad. So basically, exactly the same temperatures. My personal preference is the 'yeasty' one but from what I read, a normal starter has lactobacillus, which would lead me to think that the 'lactic acid' smell is probably quite normal. Of the two, it's my second favorite smell.
    – Mark
    Commented Apr 29, 2020 at 11:24
  • @Mark all starters will accumulate a population of both yeasts and bacteria. My hunch is you have different populations, given that one was started elsewhere. It would be interesting to build them up independently and bake with them. See which one is preferable.
    – moscafj
    Commented Apr 29, 2020 at 16:45

Starters continue to epigenetically adapt to their food source over time. This happens over weeks, months and centuries. With the one you have made, just keep feeding it often. I have bought and made many over the years and I always prefer the ancient ones. There's one in particular I like from the Ischia Island bakery. I've actually thrown all the others away.

Your starter is an infant, but over time you will be able to run it with a level of sourness that you like. When it's dormant it will be sour. There is a process called "washing" that Ed Wood promotes, which is basically putting enough water into the culture to make the volume 3-5 times larger, stirring it up, pouring off 4/5ths of that water and then adding flour into what remains until it's the consistency that you intend to run your starter at. You can repeat this process several times if it still tastes too sour. You can also use this process to decontaminate mould. The LAB will absolutely outcompete the mould spores with a few washings.

A thicker consistency is probably more advantageous for the home baker because you have more flexibility with your time and it's easier to gauge the activity level.

I find the best sourdough flavours develop with a slow fermentation at 18°C, despite S. Cerevisiae being so active at 25°C. I also think more subtle umami flavours will develop from the gluten if your starter is not very acidic.

Good Luck!

  • Such good information here.
    – Mark
    Commented May 5, 2020 at 0:25

The starters I have been making recently are nothing but flour and water. I feed them with 1/3 starter, 1/3 flour and 1/3 water and they become very active after 3-4 days, tripling or more in volume each time I feed them.

I would describe the aroma as yeasty but also slightly effervescent and reminiscent of beer, very slightly like alcohol. My kids don't like the smell because they think it's too much like beer. However they love the resulting bread.

The "starter kit" that you got may have included some commercial yeast or something besides natural wild yeast and so may have a very different aroma and rising characteristics. Doesn't mean it's bad necessarily but will likely be different than natural yeast.

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