Why are we removing "most of" the starter?


Total newbie, both to the site, and to sourdough in general.

Started last thursday and my starters are looking go-o-od! (as far as I can tell by comparing to online pictures)

However, I realize I've skipped one step in the receipe a few days; the "remove half/most of the starter", before feeding. Does this matter? Why do we remove it at all?

My starters are doubling and bubbling, but I am so exited to see if they will actuallye do what they are supposed to.

341 users have voted.


farinam's picture
farinam 2015 April 14

Hello KristinePG,

As a conglomeration of biological entities, your starter's yeasts and bacteria produce wastes.  A major one is carbon dioxide which makes the bubbles and causes the volume expansion that you get.  But there others like alcohol, lactic acid, acetic acid and any number of other compounds.  If some of these get to high enough a concentration, they will have an adverse effect on the activity and blend of biology in your culture.  But a good balance is also necessary to keep any nasties under check and to allow the good guys to thrive.  Discarding half and replacing it with fresh reduces the concentration of the waste products to half of what it was and after a few cycles you reach an equilibrium concentration that is acceptable.  Without discard, the concentration will continue to increase until it has the adverse effects mentioned before.

Also, if you don't discard, the volume of material that you have increases out of hand and you need to discard to maintain a handleable amount.  At least, that is, until your culture has stabilised which usually takes 10 to 14 days before you can be sure.

Don't get caught up in the 'but it's such a waste' syndrome.  In the scheme of things, it is only a few cents worth of flour and it is done for a good reason.

Just be aware that early bloomers can sometimes suddenly appear to go quiet and maybe smell a bit funny as the mix of creatures change but don't despair if it does.  Press on with the feed/discard regime and it will probably come back better (and more stable) than ever.

Once you have your stable culture, depending on how frequently you bake, you can keep it in the fridge and only feed it after you take some out to start your levain.  This can be as infrequently as once a week but they can be left for a month without feeding and still recover quite quickly to full strength.

Good luck with your projects.


Mike Batho 2015 April 22

Mark my words, if you don't disgard any starter, you'll end up living a Fantasia style starter nightmare with jars filling the fridge, kitchen cupboards, wardrobes etc lol. Starter breeds and multiplies like the randiest of rabbits... :)

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