The Fresh Loaf

News & Information for Amateur Bakers and Artisan Bread Enthusiasts

Sodium Hydroxide

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Pain Partout's picture
Pain Partout

Sodium Hydroxide

Finally have a bottle of sodium hydroxide (NaOH) pellets in hand, and am Hot to Trot, to try making pretzels using a lye dip.  How much NaOh should I use to how much H2O??


I am assuming that this stuff should be perfectly non-reactive with stainless.  I can use a stainless spoon, skimmer, or ladle, and use a stainless beaker to mix/hold the solution?  Can I store the "used diluted solution"  in Nalgene?  If I store it in a glass bottle with a plastic lid, will there be "issues"?


Don't have any latex gloves, but have thousands of one-time-use Nitrile gloves.  Nitrile not affected by the strong caustic?  Was going to use parchment between the dipped pretzels and an aluminum baking sheet.  Will I damage my pans? Can I line the pans with heavy aluminum foil, then cover with parchment?  Good idea? Bad idea?


Best ideas for diluting the lye, and what materials are "compatible" with the remnants of the caustic solution when baking would be appreciated. 

wanamoka's picture
wanamoka

When I was a chemistry teacher, my class made soap.  I had one student put their soap on the aluminum window sill because of lack of space.  It ate a big hole in the aluminum. 


 I'd be careful of the pans. 


Nitrile gloves are great. Use Goggles and an apron.  Remember if it makes soap, it will burn your eyes and hands.  Add lye to cold water and to be extra safe over a bowl of ice because the reaction creates a very hot solution.  Ventilation is important.


If you want to neutralize the left over NaOH just use vinegar until a pH paper shows neutral.


Dilutions are made with water only.  A 1M solution of NaOH will take 40 grams / liter of water.


for more information see   http://marcofrom.com/archives/2008/04/bretzel_vs_pret.html  lye dilution 1250 g Water and 50 g of Lye


 


 

alconnell's picture
alconnell

I've made pretzles dozens of times using lye solution.  I use granulated, about 1-2 TBS per liter of water.  It is a very mild solution, but caution is still necessary.  I use plastic mixing utensils and a glass bowl, putting leftover solution in a glass jar with a plastic lid.  It can be reused over and over again. 

Yerffej's picture
Yerffej

A good dose of caution is necessary when working with lye.  The damage that lye can cause is generally permanent and so protection of skin and eyes is essential.


Jeff

Ford's picture
Ford

Nalgene is the name of a company who makes bottles from several different plastics.  Some would be safe to use with sodium hydroxide and some would not.  Polyethylene and polypropolene should be ok.  I would avoid storing the sodium hydroxide in glass, because the aqueous solution will etch the glass and give you sodium silicate in the water.  This may not be harmful, but why would want it.


Avoid aluminum.  Sodium hydroxide reacts violently with this metal.


Ford

Pain Partout's picture
Pain Partout

Appreciate everyone's input immensely.


I definitely  will not consider using aluminum with sodium hydroxide. Call me chicken. I also didn't realize that adding the NaOH to water must cause an exothermic reaction?  My chem days are many years behind me, and I was pretty much a flop at chemistry anyway. 


Thanks, as well,  for the tips to store the solution in polyethylene or polypropylene.


If I use parchment on a stone for baking, will any residues, or vapors possibly harm my stone?  My peel is aluminum. Will a brief contact be injurious? 


Can I use a Silpat (or other brand) silicone mat over a steel pan for baking? I am assuming that the diluted dipping solution will be so weak that any residue on the pretzels will not cause problems in baking? Is silicone impervious to the diluted sodium hydroxide solution?


I can work "under a hood" with mixing, "dipping" & and holding prior to baking,  by using my great "high-power" rangehood fan.  But, when I bake, could there be other issues? 


Gads.  I am starting to get spooky about using this stuff.

asicign's picture
asicign

I've just started using NaOH for my pretzels too. I can provide some input to your questions.  I don't store my NaOH solution.  A pound of NaOH will last me a very long time, and I don't want to take chances with a container spilling.  Although the solution is weak, in the oven, the water evaporates, so it can get quite concentrated.  I haven't seen it eat through parchment paper, but I don't think it would harm a baking stone.  I do not believe there any fumes given off. If some of the solution gets on your peel, just wash it off.

Ford's picture
Ford


Gads.  I am starting to get spooky about using this stuff.



Great!  You should be very careful it is dangerous.  A drop in your eye could cause blindness.


I have not made pretzels, but I have eaten a lot of them.  My knowledge of sodium hydroxide (aka lye, caustic soda) comes from my being a chemist.  The Silpat should be ok.  As asicign said, the weak solution will become concentrated as it evaporates.  I would suspect the lye will not harm the baking stone, but be careful of a lye residue left on the stone and wash that off with  plain water.  Don't forget to wash off your aluminum peel after each use.


Ford

Pain Partout's picture
Pain Partout

Great further comments, asicign, and Ford.   Should I rinse the peel with diluted vinegar very briefly to help neutralize the caustic quicker?  Sounds like water is sufficient. Ours is hard, even though "softened".


Ford,..I have eaten lots of pretzels too.  The only times I have tried making them, they taste more like rolls, than pretzels.  I keep hoping for some elusive alchemy that will make them taste more authentic. They take some time to make, so turning out a mediocre pretzel is very disappointing.


Many thanks.....


 

Ford's picture
Ford

Just rinse off the peel with water.  Forget trying to neutralize the lye.  Pour it down the sink and flush that with water.  Aluminum is a very reactive metal.  Around the neutral area, say pH  6 to 8, The aluminum will have very little corrosion but as you move away from that point the corrosion rate increases rapidly.


Ford

Pain Partout's picture
Pain Partout

Thanks, Ford, for more in-depth dialogue re using aluminum peels with a caustic solution. 


If you had been me teacher in chem, ..I might have understood all of those "molecules" better? 


Didn't want to "pit" my peel (ooooh...baddd).  I feel better now about using my aluminum peel with possible residues from the caustic pretzel bath.

copyu's picture
copyu

I did a little 'kitchen science' project on various alkalis called "Truth regarding Lyes". You can search it, above


My solutions, all "3%", showed that NaOH has a pH of at least 13.7, which is close to the max. That will definitely make 'soap' from the tiniest bit of fat in any of your previously-used metal vessels, including stainless steel...that 'soap' would not make your pretzels taste better. It may be insignificant, taste-wise, but I always avoid metal containers when using NaOH for foodstuffs, just in case...


I'd use one of the recommended plastics (ie, polyeth/polyprop, preferably NEW or VERY CLEAN) or a well-rinsed glass container for any dipping or mixing of the lye


There's no danger from the lye dip after oven temperatures


[Storage in a plastic container is fine, if you're careful, but put scary warnings on the bottle, please!]  


Cheers,


copyu


PS: The German suppliers of my NaOH recommend 3.5-4.0 grams of pearls per liter of water


[edited to answer the actual question asked "How much...? ;-) ]

Ford's picture
Ford


My solutions, all "3%"...


PS: The German suppliers of my NaOH recommend 3.5-4.0 grams of pearls per liter of water


[edited to answer the actual question asked "How much...? ;-) ]



This must confuse some people, including me.  Do you use a 3% solution, i. e. 30g/l (grams/liter) or, do you use 0.3% solution 3g/l?

copyu's picture
copyu

Hi Ford,


30g/l


Manufacturers say 35 to 40g/l


How careless of me!  What they said was aim for "3,5 - 4,0%". I edited my post too hastily as it was getting too long-winded (one of those 'senior moments')


Sorry for any confusion


copyu


Happy Thanksgiving!

Ford's picture
Ford

Happens to all of us.  Yes, it does!


Ford

abdosoliman's picture
abdosoliman

 If your aim to have a alkaline solution you can try soda or sodium carbonate 8 g./l should equal 4 g./l sod. hydroxide. Sod. carbonate dissociate in water and produce alkaline condition similar to sod. hydroxide but not as corrosive.

alconnell's picture
alconnell

I wish there wasn't so much fear about using lye.  YES it is potentially dangerous.  The biggest danger comes during mixing the powder/tablets with water.  I always use gloves and safety glasses for that.  After that, it is a 3% or less solution.  Be cautious when using it, and it is perfectly safe.  Folks, this is the same stuff used in drain cleaners in a much less concentrated state once mixed.  I use plastic and glass and that's it when mixing/using it.  I use silpats to bake the pretzels with no problem.   I reuse the solution 5-10 times with great results.  It is the only way I have found to get the true taste of german pretzels.  


Lye/Sodium Hydroxide has been used in making corn tortillas for many years. 


RANT: Being safe when trying something new requires research.  I just tried out my new turkey fryer the other day, after reading the manual completely, going online and reading about it, and using my head to figure out how to be safe while doing it.  END OF RANT

Pain Partout's picture
Pain Partout

Have not been at this forum for several days, as preparations for Thanksgiving seemed to get in the way of most of my life.  I have enjoyed the comments on this thread very much.  


Alconnell, I greatly appreciate your comments about how you have used, and stored,  the Lye solution.  


I grew up in a private laboratory, as my Dad was an independent biological consultant with degrees in chemistry and biology. I was a total failure in my father's eyes, as I always had problems with chemistry.  Later in life,  I worked for a university research facility playing with all kinds of dangerous stuff. 


I have learned, all of my life, to be careful with reagents, solutions, and handle stock chemicals, etc, with caution and safety.


The greatest danger would certainly be storing/handling the "raw chemical" (sodium hydroxide).  Not being a chemist though, I have had a lot of questions about baking with it. Everyone's comments here, have been very good.


Alconnell, what do you material do you use as a ladle/skimmer?  Do you "dip" with a plastic fork?


Wonderful input, all......

PCSP's Finest's picture
PCSP's Finest

Ford, et.al.

Thank you for the ratios and good advice on handling but even with all that I have a follow-up question. In this photo they are using some type of large barrel to hold their lye solution and dipping pretzels into just before baking. It looks like stainless steel to me. They are also using a metal  screen to draw them up out again and toss onto a staging area for the person operating the oven.  I know they are heating the solution which would require a metal container. My question is: What type of metal would be safe for this?

Jump to 20:20 for scene

Jump to 20:20 for scene




 

 

BBQinMaineiac's picture
BBQinMaineiac

Stainless steel would be fine to use if it's clean. You needn't get all anal about it either, just make sure it's clean. You don't put bowls away greasy right?

Note, a comment was made above about the lye being used in drain cleaners. That's true, but I want to add, do not use drain cleaner for the pretzel dip. The dry crystal drain cleaners I see today have other things added to them to make them  better at cleaning drains. You don't want to dip pretzels into drain cleaner.

That brings up disposing of the solution. Just carefully put it down the drain. It won't hurt a thing. Of course that's if you don't store it for a future use. There's no need to neutralize it whatsoever since the solution will be far weaker than pouring drain cleaner into the same drain. Just don't splash it. I'd rather see you take more precautions than really necessary than regret precautions not taken for the rest of your life. BTW, water will effectively dilute and take care of any residue. More water is better than less. But to be sure, it won't hurt to wipe with vinegar as a final wipe on say a countertop.

I worked in a paper mill  at one time and there we made CaOH on site which is both temperature hot and chemically hot, extremely so. It eats the wood chips and leaves the cellulose. It's so chemically hot that if one got any on the skin you could watch it eat right through it and into the meat. I know; it happens. We had showers "right there" and went under them to flush it away if we got any on us, and we did. Those showers didn't fool around, it was a deluge. My point? A water flush is sufficient. Oh, and everything that touched that concentrated CaOH in that department (recausticizing) was made of stainless steel.

Xenophon's picture
Xenophon

It doesn't react with that.  But be very careful, only add the solid to a large quantity of cool water.  And be extra careful when heating it as hot solution is even more caustic.  I would not, ever, consider storing it.  Just too risky, especially if you have pets or kids around, it's not worth it.  BBQinMaine gives good advice.  If you ever spill it on yourself, immediately rinse with abundant water.  If you get it over your clothes and it comes through, drop everything, jump in the shower and put the water on max, then strip.  Do not bother taking of your clothes before showering.  And wear safety glasses.

NaOH gives the best results for pretzels but I don't use it, too risky for me.