# Fabulous Baker Brothers Recipe (Hobbs House): Problem with the maths

Billsykesdog

I apologise in advance if this subject has been covered elsewhere.

This week I have been following the recipe for sourdough culture from the Fabulous Baker Brothers cook book but I do not understand the maths.  To start the culture they recommend 75g flour + 75g water.  Repeat everyday for a week. (5 x 150 = 750g). The recipe for a sourdough loaf requires 300g of culture (including 150g flour/water from the day before). So far so good.  The plan for feeding the culture states that you start with 75g of sourdough, feed with 75g flour and 75g water (225g). Add 150g flour/water the day before you plan your next bake (375g) thus leaving 75g of culture to start the whole process over again.

After baking my first loaf I am left with 600g of culture when I only need 75g so why was it necessary to start with 750g in the first place? Is it better from a quality point of view to keep a large reserve or a small one?

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## Replies

farinam 2014 January 17

Hi Billsykesdog,

I am not familiar with the book you refer to, but in my experience, when establishing a culture (and I recommend reading SourDom's beginners blog on this site - link at top right of page), during the establishment phase, half of the mixture is discarded at each feed.  That would limit the amount that you end up with at the end of this phase.  This method, as you report it, leaves you totally reliant on the survival of your aliquot (75g) which could be a bit hazardous.  My inclination would be to keep a larger quantity and draw out and replace what you need to start a loaf.

I keep a couple of hundred grams as stock (kept in the fridge) and take out an aliquot that is then fed to make the dough.  In my general case, I take out 90g and immediately replace with 45/45 flour and water so that the amount of stock stays essentially constant.  It does decline a bit in mass due to losses by escaping CO2 and scrapings so every once in a while I up the addition to 50/50.  After the new feed material is mixed in, it goes straight back into the fridge until the next time I bake (usually once a week).  I have left it for a month while on holiday and it was fine after a couple of feeds.

Hope this helps and good luck with your projects.

Farinam