The Fresh Loaf

News & Information for Amateur Bakers and Artisan Bread Enthusiasts

Starter growth - Upscaling limits?

TangoDancer's picture

Starter growth - Upscaling limits?

I maintain about 3/4 cup by volume of starter in my fridge.  Some recipes I've been looking at are asking for 1 cup of starter.  So, my question, by way of example, is that I presume I could take about 1/2 cup of the starter add 1 cup flour (~113g)  and 1/2 cup water (~113g), let ferment overnight and then use 1 cup of the newly fermented starter in my baking.

At some point in time it seems to me that, depending on the recipe, one could add so much flour/water that it would take longer than overnight for the population to grow to give a strong/viable enough starter.  For example, and this is just to articulate the problem, not a real world example, but if one added 5 cups of flour and appropriate water to 1/2 cup starter, it seems that it would take a considerably long time for a viable starter, and it might even not work.

So, is there a rule of thumb regarding how to upscale starter?  For example, I could see a rule that says, for every gram of starter, the maximum you would want to feed it is 4x.  So, for 40g of starter you might not want to go over 120g flour (and appropriate water).

I apologize in advance for the wordiness, but I couldn't figure out how to articulate this concisely!




barryvabeach's picture

Tango,  yes ,  it is hard to word the question,  though of course,  I don't have a real answer other than it depends.  

Normally, we refer to feeding schedules by a ratio where the first number is starter, the second is water ( I think ) and the third is flour.

One common ration is 1:1:1 - so that would be 113 grams of starter to 113 gram of water and 113 grams of flour  ( While i greatly prefer grams to volume measurements in general, when measuring starter i find the whole concept of volume baffling since the volume changes over time as the starter increases in size then deflates, and of course, since it has trapped air, the idea that you could get an accurate measure by putting it into a 1/2 cup measuring spoon seems hard to understand , sorry for the rant)

The ratio of the last two numbers tell us the hydration of the starter  ( or if you are changing hydration, where you are heading too)  so a 100 :125:100 would be a 125% or liquid starter.

The ratio of the first number to the flour tells us how much food, so again, if it were 100:100:100  than the food to starter ration is 1 to 1 and we would expect it would mature quickly.

It is also very common to see ratios of up to 5 -  so  100:500:500 -  which would mean that starter would take longer to mature.   I don't think there is an actual maximum limit, though in practice, the timing may not work out all that well if you went 1:100:100 - since you might run into trouble with dough degrading.

Note that many suggest that the starter activity will vary based on feeding amounts and schedules and so if you start feeding it higher amounts of food consistently,  it will increase its activity, so that if it took 4 hours to double in volume on a 1:1:1 and you then changed to 1:2:2,  after several refreshes, it would not take 8 hours to double -  though it may take slightly more than 4. 

BTW,  many us keep a very small amount of starter in the fridge - for me, usually around 15 grams. A day or two before I want to bake,  I take it out, 1:2:2   8grams starter ,  16 water  16 flour,  then stir,  then take out 15 grams, put in a separate jar for an hour or two at room temp, then through in the fridge till next week, and when the remaining amount matures, refresh to build up enough for my baking on the weekend. 

phaz's picture

A gram of starter can inoculate a ton of flour - if given the time. I use all my starter for a loaf, then I throw in a bunch of flour and some water and just stir a couple times a day till it stops rising, add a little more and back in the fridge. I start with jar scrapings. The only rule, if you could call it that (it's really just common sense) - give it the time it needs to populate the mass. Enjoy!