Starter maintenance

A beginners guide to sourdough by a beginner

Starter maintenance

A beginners guide to sourdough by a beginner

This is a part of an in depth 'beginner's guide to sourdough baking' from CooklyBookly founder Freddy May. Click here to see the full collection. Feedback is very welcome, so please send comments to

Starter Maintenance - the fridge

If you bake every day then refreshing your starter daily is easy.

However, most people, me included, bake a couple of times a week or less. So, how do you keep the starter healthy and alive. The answer is to use your fridge. It's as simple as that.

If left in a warm place, a starter will die after a few days. But in the fridge, it can live for weeks. The older it gets the more help it will need coming back to life.

I use the following approach in 2 cases.

  1. My starter has been in the fridge for a week and I just want to bring it back to life a bit, even if I am not going to bake soon.
  2. If I want to bake and I need to bring it back to life before I build a proper levain from it. The levain is a bigger volume of starter that I can bake with. I discuss this in the Building a Levain section.

Refreshing your starter

Unless you bake every day, you'll be keeping your starter in the fridge. However, even at cold temperatures, your starter will continue to ferment. Just a lot, lot slower.

As a result, you need to bring it back to life. If you put ripe starter in the fridge the day before (or possibly even 2 days), then you can refresh and bake from that single refreshment.

If, on the other hand, your starter has been in the fridge for longer, then you will want to refresh twice. As long as you see it rise as it does at its healthiest then you're good to bake with it.

Getting ready

Below you can see everything ready to do a basic refreshment. Here's a summary of my basic refreshment from a starter that's been sitting in the fridge for a few days.

  • About 20g of starter, throwing the rest away.
  • 80g of white flour
  • 80g of water from the jug (ideally not straight from the tap).

  • a jar of old starter that's just come from the fridge
  • a clean jar ready
  • flour
  • a small jug of water (not fresh from the tap but left on a jug overnight to get rid of any chlorine) that I've warmed in the microwave to about 30℃
  • digital scales
  • spoon for the flour
  • fork for stirring

Spoon a bit of starter into the clean jar

I use a moistened spoon for this so it slips off the spoon more easily. As this is the first of 2 refreshments I am going to do to get it into prime health before I bake, I take about (and it does not need to be exact) 20g of starter.

Add warm water

I add about (not exact) 80g of water. It can be a bit more or a bit less. I stir up the starter to it dissolves nicely into the water. This makes it a bit easier to stir in the flour.

The reason I add warm water is because I want the final temperature of the starter, after I've added the water and the flour, to be somewhere around 25℃. The reason for this is that my starter will ripen quite a lot quicker than at, say, 18℃, which it would otherwise have been if I had used cold water. Don't worry too much about the exact temperature. My starter is cold, as it's come from the fridge, so I reckon on warming my water to around 30℃.

If you are refreshing a starter that was not stored in the fridge then you won't need to warm the water quite as much.

If you add hot water, you will kill the starter, so be careful here.

Add flour

I now add an equal weight of flour, my case I aimed for 80g again and missed by a bit. Doesn't matter.

Stir in the flour vigorously

Stir the flour into the starter+water mixture. Be very vigorous about this. You want to end up with a homogenous mixture. You can see that my final temperature is about 25℃.

Let it ripen (somewhere warm)

Now, we want to leave my starter to ripen. It really helps to have a warm place where the temperature is reasonably stable. Don't leave it in the sun.

I have a Brod and Taylor bread proofer, which is a great bit of kit but it's not cheap at £150 or $170 in the US. You can use an airing cupboard of the oven with the light on. If you use the oven, don't leave the heat on or you are very likely to kill your starter.

My starter takes about 6 hours to reach its peak height. Yours may take less or more time and the temperature will affect this time considerably.

Below, you can see how it takes a long time for anything to happen. Each mark is 1 hour. Not a lot happens for the first 3 hours. Thereafter, things speed up quite a bit before slowing down as it nears its peak.

If you were to leave it longer, it would start to sink back down again. You want to use this ripe starter near its peak to build your larger quantity of starter ready to bake with.

And this is what it looks like from above. Nice and frothy. Smell it, too. It smells amazing! In fact, try smelling every hour or two.