The Fresh Loaf

News & Information for Amateur Bakers and Artisan Bread Enthusiasts

Throw Away Half

flournwater's picture

Throw Away Half

It's always been puzzling to me that recipes for sourdough starters begin with a series of steps that typically include, at some point, throwing away half of the mix.  That doesn't make sense to me and, I admit, I've never complied with that direction.  My starters develop nicely and I haven't found any reason to believe that my maintaining the full batch generates any difficulty whatsoever.  So, my question to those of you with a lot of exprience on this subjet, "why am I supposed to throw away half of my starter mix during its initial development?"

rainwater's picture

I think it was explained that "throwing away half" was to keep the home baker's starter from becoming too large to be efficient for their novice baking needs.  No other reason really.  I'm sure they never throw away half in a commercial bakery.....I think professonal bakeries usually don't refrigerate their starter, and feed it once, or several times a day depending on how much they are baking sourdough. 

I use Peter Reinhart's technique for starter, but keep my starter at @75% hydration.  One thing PR is adamant about is when feeding the starter to "at Least!" double it....hence....1# starter equals 1# feed.....also triple and quadruple is okay depending on what kind of starter you want. 

I keep about 2# of when I bake sourdough, I keep 1# to feed, and the portion for the formula.....left over starter?  With baker's math, I figure out how much flour and water is in my starter and subtract this amount from the flour and water from an instant yeasted recipe......I figure it's still flour and water, and why throw it adds flavor to my yeasted dough too!

TeaIV's picture

I agree with both of you. if you don't like throwing it away, there are many threads on TFL talking about what starter "waste" can be used for. also, if you keep a small enough amount of starter, you can add it to any of your baking, which won't affect the taste too much.

pattycakes's picture

I have done it both ways-throw it away and make something with it. At first, it really bothered me to throw the starter away each day, because I maintain it at active level all the time. Now, I've become used to it, and it doesn't bother me any more. Ideally, we would be baking and refreshing every day in order to maintain the sourdough and not be wasteful. If I had a large family, I'd do it, but it might become a chore instead of a pleasure!


TeaIV's picture

sometimes, I really don't want to throw my SD starter away, and I'm not planning to use it, so I just stick it in the fridge and use it whenever.

Yumarama's picture

"why am I supposed to throw away half of my starter mix during its initial development?"

During the "initial" development - and by this I assume we're talking the first several days of your brand spanking new starter, what you'll be throwing away is likely not even "starter" but rather flour soup wherein there's a fairly good chance you're also growing a few less-than-desirable cohabitants. This would explain why you'd want to chuck it out rather than use it. 

You also cut back on your starter so you don't end up with gallons of it since quite early on you do begin to make your feeds at a ratio of 1:1:1 or 1:2:2.  For illustrative purposes, let's follow the 1:2:2 ratio and just assume we're using cups (easier to visualize) although you really would be weighing, of course.

So let's say  on day 1 morning feed, we begin with a half cup of starter. Half a cup sounds like nearly nothing, right? To that we'd then need to add twice that amount of each water and flour, so we add 1 cup water and 1 cup flour for a total of 2.5 cups. Still not that bad.

Day 1 evening feed, we're not reducing so we need to add to our 2.5 cups of starter 5 cups water and 5 cups flour for a total of 11 cups. Set it on the counter, hope it doesn't overflow everywhere and go to bed.

Day 2 morning feed, we're still not tossing away so to our 11 cups we have to add 22 cups of water and 22 cups of flour. We now have 55 cups of starter or about 3.5 gallons. Remember, this is only the third feed and we started with just a measly half cup yesterday morning. At tonight's feed, we'll have 312 cups or 19.5 gallons of starter. Just enough to fill up four of those white Home Depot buckets although you'll want at least eight of 'em so the starter can double in size.

By morning of day three, you can fill your bathtub, if it holds 97 gallons; it very well may not, and definitely won't hold the expanded starter. By afternoon, you'll also be borrowing an additional four neighbour's tubs for your 488 gallons. 

How soon before you need to move this out to a local swimming pool to continue? Well, by the end of day five, you'd be the proud owner of 305,175.8 gallons of starter. Or 4.8 million cups. Seriously. An Olympic size pool is about 600,000 gallons. By the morning of day six, you can fill two and a half of them, with leftovers.

And it hasn't even been a full week yet.

And that's why you cut your starter back down to a manageable amount each time. It's a lot cheaper to toss a little bit out than to keep it and feed it.

SourdoLady's picture

Another thing you have to realize is the fact that those yeast cells are continually growing and multiplying so there are millions more hungry mouths than what you started with. If you never discard (or use) any excess starter and you just keep feeding a few spoonfuls of flour, they are starving to death. Add to this the fact that as the mixture ferments it becomes very acidic, and will eventually reach a point where the acidity will begin to destroy the starter. It is a process of eliminating waste when you discard old starter, much like the human body eliminates its waste after it uses all the nutrients available in its food. Does that help make it seem more logical?

flournwater's picture

Yes, thank you, that does make it more logical.  Thanks ....

photojess's picture

imagine jumping in that olympic pool with all of that frothy goo, you'd be pulled under in a matter of a short time, never to be seen again!

flournwater's picture

Well, rainbowz, your very graphic description of the possibilities of how my starter might take control of the world is very enlightening.  At least I understand now why the practice of discarding 50% at various stages becomes necessary.  Still, "It's a lot cheaper to toss a little bit out than to keep it and feed it" strikes me as starter abortion.

I guess I didn't understand it entirely because I don't use the 1:2:2 method and I use my starter before it reaches critical mass so over population isn't an issue in my kitchen.

Thanks to all for your input.  This forum provides some of the most terrific help from some of the greatest people sharing a common interest that I've ever found.

noyeast's picture

I now treat my starter in two separate ways:

1) as a high activity, healthy starter for my ciabatta SD loaves.  Which is the primary reason I have a SD starter.

2) for using up "excess" starter in a quick loaf of SD bread.  In this instance the excess starter may not be in optimum condition for fermentation but its still suitable.

In the latter example, I simply mix a dough using all surplus SD starter and sufficient flour, water and salt to give me a workable dough, and proceed in the usual way.  Obviously in doing this two things occur

a) I do not end up with a loaf of optimal flavour

b) I do not end up throwing away ingredients.


flournwater's picture

I've taken to doing the same thing, Paul.  I find that making dinner rolls using the excess is a good way to redue the starter and avoid tossing it out. 

Here's one of the rolls from "excess starter" (size of hamburger bun) I made to go with the London Broil I barbequed for dinner tonight.  No yeast, just good ole starter and a bit more flour.

photojess's picture

I've been too afraid to ask this, hoping I'd come across the answer somewhere, without having to ask.

How does one incorporate a liquid starter or poolish, into a recipe that wasn't geared for it, or at least part of the original recipe?  I know about hydration now, but how do you do the math, to know how much water and flour you'd remove from a recipe, while substituting the starter?

this answer will be much appreciated!  Thanks


sphealey's picture

Don't be afraid to ask questions around here - we love questions!

Rose Levy Beranbaum has a section on converting recipes in _The Bread Bible_.  She goes through the arithmetic, but basically it comes down to having the starter be about 30% of the total weight of (flour + water) in the final dough.  Add up the weights of the total flour and water in the recipe and multiple that by .3 to get the total amount of starter needed.  From there you back-calculate to how much flour and water to add, but we would need to know what ratio you keep your starter at to do an example.

An alternative method is just to start with your usual poolish, say 150 g flour and 240 g water, and add a tablespoon or so of starter to it, mix thoroughly, and leave overnight.  That generally works!


photojess's picture

nice simple instructions, esp if a starter is 100%.  Thanks again!

pmccool's picture

Think of your starter as a horse.  Would it do well if you only fed it half as much and never cleaned out its stall?  Not so much.

So, by throwing out half your starter before feeding, you clean out the stall and get rid of the stuff that's already been digested.  Then you feed a full ration to keep the "horse" in tip-top condition.  Yeah, the analogy doesn't hold together entirely but it works well enough.

The other factor is that if you just kept shoveling food in at the recommended rate (typically 2 parts food and water to one part starter, by weight), you would very rapidly run out of containers in which to keep it.

By the way, you don't have to throw the "discard" portion away if you want to use it in other baked goods.


Heidela123's picture

I hope this helps to share the method that works for me
I feed and bake weekly or biweekly depending on need and schedule
and never toss or grow too much
Here is my method my sourdough cultures are really nice not strongly sour or weak flavored and all are vigorous and several very old old ( like more years than I can count)
I have used this technique for many any years, it works well for me so based on that and the question I guess I can share?
I keep the starters in the fridge
Have 2 cups of each ( I have 6 cultures and bake big on the weekends or Wednesday depending on work)
The night prior to baking
I take them out one at a time ( I worry a bit about cross contamination because knock wood they are so distinctly different I do not want to mess them up)
Dump each culture entirely into the bin I will use for rising
Put 2 cups water 2 cups flour into the entire starter mix it in dump half back into my starter container and put that right back in the fridge
The remaining 2 cups for the baking
Each week I bake 6-8 loaves keep two-three loaves for us ( if you hae only one maybe two this would obviously yield less ) and either donate ( food bank is always happy to see me!) the rest, freeze, sell or give it away to family/ friends

Breadandwine's picture

I use any 'discard' to make pikelets.

I use a 200% hydration - 100g flour to 200g water for my starter. Mainly for ease of use, really, it's so simple just to pour out the amount I need.

It's easy to turn this into a pikelet batter - often I add sultanas or similar to make fruit pikelets. Left overnight, the fruit plumps up lovely.

Here's my method, with pics (about halfway down the post):

Cheers, Paul

doughooker's picture

I replenish my starter just before baking, and only make enough to make the next batch of bread plus a bit more. A small amount of leftover starter is mixed with the "storage starter" and sits in the fridge. There is no discard.

doughooker's picture

Let's see if I can describe this more accurately.

8 oz storage starter in fridge

Remove 4 oz, use as inoculum (leaving 4 oz unused)

Add 4 oz inoculum to 4 oz fresh water & flour (total 8 oz)

Use 4 oz to bake (leaving 4 oz)

Add 4 oz new starter to 4 oz unused storage starter (total 8 oz, back in fridge)

PetraR's picture

In the beginning of my SD baking I felt guilty or MADE feel guilty by sticking to what I learned , which was / is  throwing out half the Starter.

I was told  that it was silly to keep a larger amount of Starter going and and and...

I am not feeling guilty anymore.

My Starter is very happy, very very healthy and makes great bread.

If I have need for the discard I use it, if I do not need it , away it goes.

I bake every second day, we eat a lot of bread, we are 6 people in my house, I have a large amount of Starter but also a lot of bread to bake.

To keep just a small amount of Starter and build that up to get the amount I need is not practical for me. 

If I do not bake much for a few weeks it goes in the fridge.