The Fresh Loaf

News & Information for Amateur Bakers and Artisan Bread Enthusiasts

raw vs. cooked potatos in bread

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johnsankey's picture
johnsankey

raw vs. cooked potatos in bread

If you use raw PEI potatos in bread, they clobber the yeast; the same potatos cooked are fine (see http://johnsankey.ca/bread.html#potato) I know that PEI mandates pathogen control to an extent that systemic fungicides are required - residues of them would be deactivated by cooking. There are notes on the web about a "rope fungus" in potatos that kills yeast, but PEI wouldn't allow anything like that to raise its little nose for a second, they even ban backyard potato growing they are so paranoid about their GDP. So, my question is: is it those fungicides that are the problem? Or, do some potato varieties present more problems than others (Yukon Gold, Russet, etc.)?


I haven't been able to find Canada certified organic potatos, which would be an obvious experiment...


John


 

dwcoleman's picture
dwcoleman

I wonder if starch plays a role in this.  You could cut up some raw potato and soak it in water for 24 hours, rinse and then try using it.

johnsankey's picture
johnsankey

Thanks for the thought - it's on my to-try list.


John


 

Mini Oven's picture
Mini Oven

Looked it up.  Gosh!  I thought it was something other than "Prince Edward Island."  


Rope can be found on the ground and in contact with dirt.  It rears its ugly head quite a bit.   Once on kitchen surfaces, a pain to get rid of.  Using cooked potatoes and other cooked roots in the dough reduces the problem and risk.

Mini Oven's picture
Mini Oven

I think cooking the potato is very much like making a paste with flour and water and cooking it.  It adds lots of moisture to the bread and soft texture to the crumb.  One gets similar results adding cooked cereals and grains.  Pre-gelatinized starches is what's going on.   Now potatoes do vary in texture, and thus their uses.  

williampp's picture
williampp

I have baked bread with grated raw potatoes in it twice now and no problems.


They were bought at our local store.


I will be trying grated pumpkin next time.


I did the bake from a cold oven.


Bill

johnsankey's picture
johnsankey

grated squashes work fine for me, Bill - should be no problem.


How much raw potato did you add per cup of flour?


John

williampp's picture
williampp

172g Starter


272g Bread flour


201g Whole wheat flour


244g Water


7g Vinegar, this should have been pineapple juice, cupboard was empty


11g Salt


158g Grated Spuds


36g Oil


This comes out at 60% hydration, but the spuds add a bit, so may be 65%???


Spuds come out at 28% (Bakers %)


Baked covered (first 10 minutes) from cold oven set at 210C for about 40 minutes


Bill

johnsankey's picture
johnsankey

Bill, I'm trying 30% potatos and usually aim for 60% hydration. According to the USDA, raw potato is about 62% water available for flour hydration, so your actual hydration is quite a bit more than mine. Still, though, you're telling me I need to look for another source of potatos. I've located an organic potato farm in Quebec and will try to get some from them.

Keep you posted.

John

johnsankey's picture
johnsankey

Half a dozen more experiments, and the result is clear - two different Canadian sources and three different types of raw organic potatos (white, yellow & red flesh) all work fine; two more PEI farms than the one I started with, and one Ontario one, from regular bins all kill the yeast. So, go organic or cook yoour potatos if you're in Canada.

John

 

williampp's picture
williampp

Good to see you are having success with the potatos.

Last week I tried pumpkin & onions with sourdough

Pumpkin OK but the onion did not rise as much as the pumpkin

I made the mistake of putting them in the same baking tin

During the rise the onion rise was 60% of the pumpkin

Bill