What a great article. I dived into the sourdough world when I discovered I was allergic to wheat. A long ferment with liquid starter has worked wonderfully to break down whatever I'm sensitive to. Tests say I'm allergic to the bran, germ and the gluten components. Do you think a stiff starter would be more or less effective at the breakdown of the wheat flour?

This is great info. I think I will do a side by side compare once I get some stiff starter made. Heading to the kitchen to do it now! One question, regarding discard....I make a number of discard recipes. What impact would the stiffer discard have on those uses? Flavor or texture or anything? Like, the sourdough pizza dough on the KAB site is a go to for me. Do I keep the stiff and the liquid discards separated or can I combine them?

Sharon - I think it should be fine, generally, but if the recipe is sensitive to hydration, you might want to add water to make up for what is missing when using a stiff discard. The flavor might be a little different, but probably not noticeably so.

Okay. I just found it confusing that the lead-in says, “here’s one containing 25% prefermented flour, but the header of the white chart below it says (10% prefermented flour).

The table showing stiff starter maintenance at 25% prefermented flour is actually the table for converting stiff to liquid. Here's what I get 25% prefermented:

100g. 200g. 300g. 400g. 500g

F. 43g. 86g. 129g. 172g. 215g

W. 35g. 70g. 105g. 140g. 175g

S. 22g. 44g. 66g. 88g. 110g

Is this right?

Otherwise, very very helpful information. As per usual

And another question: If you choose to use stiff starter rather than liquid starter (or vice-versa) how does that affect the weight of starter required?

It matters in two ways: the amount of prefermented flour called for in the recipe, and the overall hydration of the dough, both of which you'll want to keep constant. So if you switch from one to the other, you'll want to make sure the amount of levain you use still gives the desired PFF, and to add or subtract water from the final dough to make the hydration come out right. The best way to do this is work with a formula that has the hydration of the levain accounted for! (I'll share some formulas soon in a follow up post.)

I've been making semi-stiff starter & levains automatically since I switched from King Arthur's bread flour to Cairnspringsmills Expresso flour. 🤷🏼 Plus adding freshly milled flour to the mix will make Sir Bobby Farts-Alot dome!! 🤣 It's true that he stays fresh longer in the fridge when fed on the stiff side!

Hi Andrew! I made a spreadsheet for checking the calculations in your tables. My values differ by a few grams here and there, except for Table 2 (converting 75% starter to 100%). The amount of starter there seems high — 18g of starter in a 100g total mixture would give closer to 20% PFF, right?

Let me know if you're interested in having the spreadsheet — I'd be happy to send it on by email. I made it generalizable so you can just input your initial starter hydration, your final desired starter hydration, your desired % PFF, and the amount of starter you want to make and it'll spit out rounded the amounts of flour, water, and starter rounded to the nearest gram. It also has calcs checking for each of the tables in this post.

(I hope this doesn't come across as pedantic — I was just passing time while running a column in lab this afternoon)

Hm ok I'm maybe misunderstanding how you're defining % PFF. Is it a percentage of the total final starter weight or of the total weight of flour in the final starter? I was assuming the latter. But if it's the former, then Chart 2 is fine but I think the other three charts need to be adjusted. (For Chart 1, if the initial starter is 100% hydration, then 11g starter has 5.5g flour, which is only ~6% of the total 100g starter. But if using the latter definition of % PFF, then the 5.5g of flour *is* ~10% of the total flour in the starter (5.5g / (5.5g + 51g) = 0.097).)

Actually, you are correct that table 2 was wrong, and I have updated it. (It was correct originally, I think! UGH)

PFF refers to the amount of flour in the final mixture/dough that is fermented before it is mixed, relative to the total amount of flour present, not the total weight of the mixture. This amount is constant no matter the hydration of the original preferment, the only difference is the amount of water it might contain, which dictates how much water gets added to make something of the desired final hydration.

IOW, 100g of 75% hydration starter is 57g flour and 43g water. 10% of 57 is 5.5 (rounding, obviously), which leaves 51g flour. 43-5.5 (since the initial hydration is 100%,) = 37.5, or 38 when rounded up.

And 100g of 100%-hydration starter is 50g flour and 50g water. 10% of 50 is 5, and there is 5g of flour in 8.75g of 75% starter. So 50-5 = 45g flour. And 50-3.75= 46g water.

Thanks for making me rethink my "corrections", I've now updated and double-checked everything. (Table 4 was off too, but only because I messed up all the greater-than-100g numbers.)

Ok, that makes sense! I can send on the spreadsheet I made via email, in case it could be useful (and maybe/hopefully save some calculation headaches down the line). The numbers I have more or less match yours now — any differences are 1-2g, mostly due to choices in rounding I think.

Hello Gabriel, any chance you would be kind enough to email me a copy of your spreadsheet at catahullic AT gmail dotcom ?

I'm pretty sure that some of these conversions/calcs being made will make more sense to me if I look at the cells of your spreadsheet as opposed to reading the words of the article.

How much longer do you think I can go without refreshing if I switched to a stiff starter? Right now I'm trying to keep my liquid starter "healthy" by doing so every 7-10 days.

I use plastic spoons to mix my little refreshes--I need to maximally minimize any flour going into my apartment pipes--and 75% is way too stiff. I couldn't mix it. OH WELL.

You wrote, "many liquid levains are maintained at 125% hydration, which is 20% higher in hydration than those held at 100%". Don't you mean "25% higher"?

You wrote that a benefit of liquid starters is "Liquid starters are loose enough to be quickly and easily stirred mid-fermentation, in order to oxygenate them for a boost of activity." I use my food processor to mix my 50% hydration stiff starter and I *think* that provides ample oxygenation.

You wrote that the math for the tables is annoying. I think that if you used round numbers of flour for each column (e.g., 100 g, 200 g, 300 g, etc.) it would be less annoying.

2) But that's not the same thing as oxygenating the culture (and removing CO2 from it) mid-proof, which is a specific technique. I do it sometimes, and the culture moves much more quickly after it is done (and rises taller), in my experience.

3) But tables are not the same thing as math. Tables that start with an amount of flour that is a multiple of 10 are easy to read, but then you end up with a wonky amount of starter. The point of the table is to have *final amounts* of a round number. But both work. And either way, you have to do annoying math to determine the numbers (or use a spreadsheet).

Baking in a NYC hot and humid kitchen in the summer, I intuitively kept a stiffer starter. Your info is so enlightening. Began a real stiff starter a week ago, baking tomorrow. Will report. BTW made your burger/dog buns from your method in Edible Boston. Fantastic buns and so easy. Many thanks.

Perhaps I am missing something here but it seems to me that we are talking about a minuscule amount of flour/water/etc. I recently made a sourdough with 800 gr water, 900 gr whole white flour, 100 gr whole wheat flour, 20 gr salt, and 50 gr starter. How much difference in grams in this overall recipe is there going to be between a 75% starter and a 125% starter?

Abe - The overall hydration from loaf to loaf does not change, only the hydration of the starter. (If you use a lower hydration of starter, you need to make up for the missing water in the loaf.) And the difference between 125 or 100% and 75% hydration is significant enough to have distinct effects.

Fascinating. Thanks for this thorough explanation.

What a great article. I dived into the sourdough world when I discovered I was allergic to wheat. A long ferment with liquid starter has worked wonderfully to break down whatever I'm sensitive to. Tests say I'm allergic to the bran, germ and the gluten components. Do you think a stiff starter would be more or less effective at the breakdown of the wheat flour?

Are the last two tables meant to be the same? Personally I use the 'fudge it' method when converting from liquid to stiff.

no, my bad, I made a mistake cutting and pasting it in for the 75th time. I've updated it now, thanks for the heads up.

This is great info. I think I will do a side by side compare once I get some stiff starter made. Heading to the kitchen to do it now! One question, regarding discard....I make a number of discard recipes. What impact would the stiffer discard have on those uses? Flavor or texture or anything? Like, the sourdough pizza dough on the KAB site is a go to for me. Do I keep the stiff and the liquid discards separated or can I combine them?

Sharon - I think it should be fine, generally, but if the recipe is sensitive to hydration, you might want to add water to make up for what is missing when using a stiff discard. The flavor might be a little different, but probably not noticeably so.

Got it, thanks!!

Interesting information. I noticed the very last cheat sheet, “And here’s one containing 25% prefermented flour...” is labeled 10% prefermented flour.

already fixed, Jan!

Okay. I just found it confusing that the lead-in says, “here’s one containing 25% prefermented flour, but the header of the white chart below it says (10% prefermented flour).

No worries.

It was confusing because I pasted the wrong chart there, I’ve corrected it now

Thanks for this. I found it to be your most helpful post yet! I'd also like to see your take on converting yeasted formulae to sourdough.

it's on the list for the book, and here too, someday!

The table showing stiff starter maintenance at 25% prefermented flour is actually the table for converting stiff to liquid. Here's what I get 25% prefermented:

100g. 200g. 300g. 400g. 500g

F. 43g. 86g. 129g. 172g. 215g

W. 35g. 70g. 105g. 140g. 175g

S. 22g. 44g. 66g. 88g. 110g

Is this right?

Otherwise, very very helpful information. As per usual

already updated!

And another question: If you choose to use stiff starter rather than liquid starter (or vice-versa) how does that affect the weight of starter required?

It matters in two ways: the amount of prefermented flour called for in the recipe, and the overall hydration of the dough, both of which you'll want to keep constant. So if you switch from one to the other, you'll want to make sure the amount of levain you use still gives the desired PFF, and to add or subtract water from the final dough to make the hydration come out right. The best way to do this is work with a formula that has the hydration of the levain accounted for! (I'll share some formulas soon in a follow up post.)

Excellent post Andrew!

I've been making semi-stiff starter & levains automatically since I switched from King Arthur's bread flour to Cairnspringsmills Expresso flour. 🤷🏼 Plus adding freshly milled flour to the mix will make Sir Bobby Farts-Alot dome!! 🤣 It's true that he stays fresh longer in the fridge when fed on the stiff side!

Hi Andrew! I made a spreadsheet for checking the calculations in your tables. My values differ by a few grams here and there, except for Table 2 (converting 75% starter to 100%). The amount of starter there seems high — 18g of starter in a 100g total mixture would give closer to 20% PFF, right?

Let me know if you're interested in having the spreadsheet — I'd be happy to send it on by email. I made it generalizable so you can just input your initial starter hydration, your final desired starter hydration, your desired % PFF, and the amount of starter you want to make and it'll spit out rounded the amounts of flour, water, and starter rounded to the nearest gram. It also has calcs checking for each of the tables in this post.

(I hope this doesn't come across as pedantic — I was just passing time while running a column in lab this afternoon)

deletedJul 13, 2023Comment deletedHm ok I'm maybe misunderstanding how you're defining % PFF. Is it a percentage of the total final starter weight or of the total weight of flour in the final starter? I was assuming the latter. But if it's the former, then Chart 2 is fine but I think the other three charts need to be adjusted. (For Chart 1, if the initial starter is 100% hydration, then 11g starter has 5.5g flour, which is only ~6% of the total 100g starter. But if using the latter definition of % PFF, then the 5.5g of flour *is* ~10% of the total flour in the starter (5.5g / (5.5g + 51g) = 0.097).)

edited Jul 13, 2023Actually, you are correct that table 2 was wrong, and I have updated it. (It was correct originally, I think! UGH)

PFF refers to the amount of flour in the final mixture/dough that is fermented before it is mixed, relative to the total amount of flour present, not the total weight of the mixture. This amount is constant no matter the hydration of the original preferment, the only difference is the amount of water it might contain, which dictates how much water gets added to make something of the desired final hydration.

IOW, 100g of 75% hydration starter is 57g flour and 43g water. 10% of 57 is 5.5 (rounding, obviously), which leaves 51g flour. 43-5.5 (since the initial hydration is 100%,) = 37.5, or 38 when rounded up.

And 100g of 100%-hydration starter is 50g flour and 50g water. 10% of 50 is 5, and there is 5g of flour in 8.75g of 75% starter. So 50-5 = 45g flour. And 50-3.75= 46g water.

Thanks for making me rethink my "corrections", I've now updated and double-checked everything. (Table 4 was off too, but only because I messed up all the greater-than-100g numbers.)

Ok, that makes sense! I can send on the spreadsheet I made via email, in case it could be useful (and maybe/hopefully save some calculation headaches down the line). The numbers I have more or less match yours now — any differences are 1-2g, mostly due to choices in rounding I think.

Hello Gabriel, any chance you would be kind enough to email me a copy of your spreadsheet at catahullic AT gmail dotcom ?

I'm pretty sure that some of these conversions/calcs being made will make more sense to me if I look at the cells of your spreadsheet as opposed to reading the words of the article.

Thanks in advance. Jay

Absolutely! I'll send it your way now. Let me know if you don't get my email and I can always resend it

How much longer do you think I can go without refreshing if I switched to a stiff starter? Right now I'm trying to keep my liquid starter "healthy" by doing so every 7-10 days.

I think you could eek a few extra days out of it and/or keep it happier at 75%!

It will have to remain less happy.

I use plastic spoons to mix my little refreshes--I need to maximally minimize any flour going into my apartment pipes--and 75% is way too stiff. I couldn't mix it. OH WELL.

You wrote, "many liquid levains are maintained at 125% hydration, which is 20% higher in hydration than those held at 100%". Don't you mean "25% higher"?

You wrote that a benefit of liquid starters is "Liquid starters are loose enough to be quickly and easily stirred mid-fermentation, in order to oxygenate them for a boost of activity." I use my food processor to mix my 50% hydration stiff starter and I *think* that provides ample oxygenation.

You wrote that the math for the tables is annoying. I think that if you used round numbers of flour for each column (e.g., 100 g, 200 g, 300 g, etc.) it would be less annoying.

1) yes, corrected

2) But that's not the same thing as oxygenating the culture (and removing CO2 from it) mid-proof, which is a specific technique. I do it sometimes, and the culture moves much more quickly after it is done (and rises taller), in my experience.

3) But tables are not the same thing as math. Tables that start with an amount of flour that is a multiple of 10 are easy to read, but then you end up with a wonky amount of starter. The point of the table is to have *final amounts* of a round number. But both work. And either way, you have to do annoying math to determine the numbers (or use a spreadsheet).

This was very helpful, thank you.

Baking in a NYC hot and humid kitchen in the summer, I intuitively kept a stiffer starter. Your info is so enlightening. Began a real stiff starter a week ago, baking tomorrow. Will report. BTW made your burger/dog buns from your method in Edible Boston. Fantastic buns and so easy. Many thanks.

Perhaps I am missing something here but it seems to me that we are talking about a minuscule amount of flour/water/etc. I recently made a sourdough with 800 gr water, 900 gr whole white flour, 100 gr whole wheat flour, 20 gr salt, and 50 gr starter. How much difference in grams in this overall recipe is there going to be between a 75% starter and a 125% starter?

Abe - The overall hydration from loaf to loaf does not change, only the hydration of the starter. (If you use a lower hydration of starter, you need to make up for the missing water in the loaf.) And the difference between 125 or 100% and 75% hydration is significant enough to have distinct effects.