Making Pizza Dough: Does metal kill yeast?

[Stultis]

I just got a pizza oven and have started making my own pizza dough. I have looked at a few recipes and most of them make the express point not to mix yeast in a metal bowl or with metal implements.

Apparently the metal and the yeast react and this 'kills' the yeast. I had a look around on the net and many people agree, but I haven't been able to find any science as to why this might occur, or to what extent you need to protect the yeast. More commonly the reference is to an old-family recipe, or "what my grandmothers, grandmother used to say." I want to trust in the grandmothers of the world, but given their involvement in the 'carrots-make-you-see-in-the-dark' conspiracy, and the fact my hair is still straight after decades of crust eating I am hesitant. Besides all my mixing bowls are metal.

I don't know much about commercial brewing and baking but from what i've seen they use metal containers and implements in a lot of their production, so there must be some limitation to metals yeast-destroying ability. I am hoping someone can shed some science on this issue, and help save future innocent yeasts from an untimely death in my mixing bowl.

[FireFox]

I use a really simple mix (with two types of yeast) and mix in metal, and bake on metal and it works fine. The mix even freezes for at least two months (based on time till consumption, rather than any specific 'science')

S

[Rider]

Ummm every bakery I have ever been in uses gigantic metal mixing bowls.

http://www.hobartcorp.com/products/food-prep/mixers/legacy-hl662-pizza-mixer/

Hobart mixers are basically the industry standard.

I'd also like to know where you are getting this info since I have watches thousands of hours of cooking shows and read hundreds of cookbooks and have never seen this mentioned anywhere.

[craig]

The advice might come from the old days when metal bowls would have included tin, pewter, copper or lead solder.  Even then it would probably only be a problem if you were using a "starter" pre-fermentation where there would be a long contact time.  Stainless steel won't be a problem.

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OK, here's the scoop on using metal utensils, bowls, etc. for bread making. If your recipe is acidic, then you should NOT use metal utensils or bowls. For example, sourdoughs are ACIDIC & you should use earthenware or glass for making & storing your starter. Other recipes might call for sour milk or buttermilk...same thing...acidic ingredients.

You CAN, however, use your KA or similar Stainless Steel bowl to mix (knead) your doughs.  The dough is not in the mixer long enough for a problem to occur.

But do NOT use a metal bowl for a long fermenting.  Acidic ingredients can pit even Stainless Steel.

Also, extremely acidic recipes (like some sourdoughs) can be ruined by reacting with metal. So, just to be sure...don't use metal with sourdoughs except for the short mixing (kneading) time.

Oh, it's also OK to bake in a metal pan ALTHOUGH I DON'T WITH SOURDOUGH BREADS. Also, the longer a dough ferments, like a slow rise in the refrigerator, the more acidic it becomes.

http://www.thathomesite.com/faq/lists/cooking/2006022630017642.html

[whitedevilbrewing]

Every pint of beer you've ever had (probably) is fermented in a SS vessel.  It's not a problem.  This includes very acidic beer fermented by bacteria that create acid, much like sourdough.

Also, I do preferments for pizza dough in my SS mixing bowl.  No pitting.

[GoodDerf]

Also use honey instead of sugar for proofing your yeast with pizza dough. Don't know why but the little buggers seem to like it more.

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Don't brewers use a tannate coating after cleaning and polishing the metal kettle, to prevent both rusting and degeneration of the beer product?  Wouldn't this  negate the effect of metal on the yeast?

[whitedevilbrewing]

I've never heard of such a thing, either among home or pro brewers.  Note also that the kettle and the fermentation vessel are two different things.

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     I know that the directions for sourdough always say to use a nonmetal container.  Maybe it really is a hold over from the days when metal containers contained bad metals.  I know copper and nanosilver is used to kill bacteria these days.

[whitedevilbrewing]

I think that's probably relevant for copper or cast iron or something, but food grade stainless really shouldn't be a problem.  (anecdote, but a common one) when homebrewers buy kegs, they are usually repurposed soda kegs, and almost always have a little bit of soda at the bottom.  That's very acidic stuff, and may have been sitting there for months.  But I've never heard of it causing corrosion or damage.  That only happens if the seal is bad and the inside is exposed to open air for a very long time (ie you find a keg in a junkyard somewhere). 

[Rider]

     I know that the directions for sourdough always say to use a nonmetal container.  Maybe it really is a hold over from the days when metal containers contained bad metals.  I know copper and nanosilver is used to kill bacteria these days.

That's the whole acid alminum/copper poisoning thing.

[cerveauxfrits]

Also use honey instead of sugar for proofing your yeast with pizza dough. Don't know why but the little buggers seem to like it more.

Honey is basically all glucose, right?  Perhaps they like it more than fructose.

[SkepticalVegan]

I make my own pizza dough in a metal bowl all the time, its always works
I dont even bother to 'prove" my yeast usually, Ive never gotten a batch of dead yeast

[GoodDerf]

I make my own pizza dough in a metal bowl all the time, its always works
I dont even bother to 'prove" my yeast usually, Ive never gotten a batch of dead yeast

I find proving the yeast makes a more consistent dough, but that could be confirmation bias, because I started doing it all the time as I became more experienced. Also it helps to make sure the water temp is right and the little guys wake up.