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!

leap's picture

The great thing about bread is that you don't have to be too exact, unlike with patisserie baking, where you have to be extremely precise. With breads you can play around.

In any given recipe there will so much flour, and so much liquid (which is usually water, but might, depending on what you are making, also contain milk).

You will know how much flour and water you have put in to create your starter/sponge/Poolish/Biga.  All you do is subtract the amount of flour and water in the starter, from the total quantity of flour and water in the recipe. 

Where you do have to be careful a bit, is to make sure that your starter is not too sour. It's a matter of personal taste, but I didn't like my first Sour Dough loaf because it was quite sour. You don't want it to overpower the flavours of the flours you are using. Even though I dislike throwing half my starter away, before feeding, I do this sometimes if I feel that it is too sour.  

My Cinq Cereale loaf contains 500g flour, and 68% water (340g), and my finished starter typically 100g strong white flour, 100g bottled water.

So when the starter is really frothy and trying to escape the jar, (doubled ot even trebled), I will add it to 400g flour and 240g water. Various flours absorb water at differing rates, so you might find that your dough is a bit floppy after the first rise (which for me takes place in a lightly oiled plastic bag in the fridge for 12 hours minimum to develop the taste letting those lactobacillus chappies get to work). Panic not. I put the dough on a lightly floured surface, squash it out into a rough rectangle, and roll it up, one way, then flatten out again and roll out the other way, four times, each time giving a very little extra flour just enough to stop your hands sticking. This reduces the moisture and the rolling up helps build surface tension for that final rise.

You can also buy wooden molds from Panisbois,, in which you can do unusual shapes for your rise and bake it in the mold. You can also make your own molds out of old fruit and veg pallets from the local market.

The flour mix you can experiment with to suit your taste. I try varying blends of Whole meal (which is finer milled), or Whole Grain (which is the same but not so finely milled), with a little Spelt, here, a little Buckwheat there, maybe some Chestnut flour as well. 

My friendly baker makes some loaves containing nothing but Spelt, or Chestnut, or Buckwheat etc etc. They are dense of course, but they taste wonderful, and you should see the line of customers waiting to buy his outrageously expensive loaves. If you are looking for ideas to fight your way out of the economic crisis, open a bakery!

I have found a French miller who grinds his own organic flours using a stone mill. The difference in taste is amazing, and if you bake the bread in a wood fired oven using oak, the result will be even better.

(You will find plenty of YouTube vids for how to make your own clay oven in the back garden. Great summer project for hubby and the kids, and I'm talking not just bread, but Pizzas, Pies, Tarts, anything you like) and it is serious fun but may add inches to the wasteline! 

I can recommend How to Build an Earthen Oven - Jas Townsend and Son Cooking Series, or the speedy version, Make and Use an Earthen Oven in 24 hours - 18th Century Cooking Series. He has loads of very interesting videos.

Got to run. Enjoy.




leap's picture

Various comments. I am not a professional baker, but I do have a fair amount of experience.

Getting the starter really going, doubling up and really bubbly can take a few days. I leave my open jar next to the fruit bowl where the natural yeasts from the grapes etc are floating around in the air. Works a treat. 

I had the same question as some of you. Why throw half the starter away each time you feed. I think this is simply because starter can become really sour, so throwing away half reduces the sourness, and the fresh flour and water which is added provides nourishment before getting a really good starter rise and then making your bread dough.

I tend to make bread once a week. Even in summer it does not get mouldy and the taste seems to get better and better as the bread matures during the week. Once my bread dough has doubled or more, and before shaping for the second rise, I cut off about 100 grams and put it in a closed glass jar in the fridge, ready for next week. So now, I never have any left over starter. 

I am in France where the artisan bakers are very proud of their stone ground bio flours. They only use natural starter, which has sometimes been handed down over generations. They NEVER EVER use commercial yeast, so there is no such thing as a sour dough starter made with commercial yeast. 

You can use the ancient Greek method which is scraping the froth off your pint of beer and mixing flour into it. This is how they used to make bakers yeast.

If you have trouble getting your starter going, try this.

Day 1 First ONLY bio flour, and ONLY bottled mineral water (not tap water, you don't know what's in it!). 50g flour and 50g water in a glass jar lid on, but loose, in a warm spot next to your grapes and bananas etc.  You should see little bubbles.

Day 2 Give a good stir, tip out half, and add 50g flour and 50g water. More little bubbles and the volume should increase

Day 3 Same again and it should really start to take off, filling the jar. If it takes 4, 5, or 6 days don't worry. It is a labour of love. It takes time. It is a living breathing entity. Give it a name. Mine is called Thing!

Once it is really doubled up and active, close the jar tight and put it in the low part of the fridge until you need it.  The night before you intend to bake. Take it out of the fridge, tip out half, and feed it, 50g flour, 50 g water. Leave it out over night in a warm spot ready for the morning.

If you are making a 500g loaf, remember that you already have 50g flour and 50g water or so, in your starter, so you only want 450g flour. My preferred mix is for 68% water by weight of flour, so I am adding another 290g water to the 50g water already in the starter. 

Flours absorb moisture at different rates, so you may want to knead in more flour before the second rise, if your dough seems floppy. 

If your loaf does flop into a big round flat bread, don't panic. Remember that all bread was like that for centures and most Middle Eastern breads are still like that today.

If I am feeling lazy, I let the Kenwood do the mixing, and I leave the hook turning slowly for 25 minutes until the dough is really smooth. I take it out, knead it for 5 minutes more, and put it in a lightly oiled plastic bag in the fridge over night. This really helps the flavours develop. I knead again in the morning, and leave to rise in a warm place.

Most imprtant thing is to experiment with different flavours. Add a little Spelt here, a little Buck wheat there, a few walnuts, whatever you fancy and enjoy. There is nothing like baking your own bread. Arab bread, Italian bread, Pita bread, Indian bread, Whole meal, Soda bread, Bannock bread. There are hundreds to try. 

Never be in a hurry. Sour dough bread takes time to rise. You can not force it. Leave it out for as long as it take to double. Same for the second rise. The longer you leave it the bigger ane better it will be.

Have fun!


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.