Sodium Hydroxide (lye)

<a href="http://en.wikipedia.org/wiki/Sodium_hydroxide" title="Sodium hydroxide" >Sodium hydroxide</a> (<a href="http://en.wikipedia.org/wiki/Lye" title="Lye" >lye</a>) makes food too <a href="http://en.wikipedia.org/wiki/Alkaline" title="Alkaline" class="mw-redirect" >alkaline</a> for bacterial growth. Lye will <a href="http://en.wikipedia.org/wiki/Saponification" title="Saponification" >saponify</a> fats in the food, which will change its flavor and texture. <a href="http://en.wikipedia.org/wiki/Lutefisk" title="Lutefisk" >Lutefisk</a> uses lye in its preparation, as do some olive recipes. Modern recipes for <a href="http://en.wikipedia.org/wiki/Century_egg" title="Century egg" >century eggs</a> also call for lye. Masa harina and <a href="http://en.wikipedia.org/wiki/Hominy" title="Hominy" >hominy</a> use <a href="http://en.wikipedia.org/wiki/Agricultural_lime" title="Agricultural lime" >agricultural lime</a> in their preparation and this is often misheard as 'lye'.

Sodium hydroxide, also known as <a href="http://en.wikipedia.org/wiki/Lye" title="Lye" >lye</a> and caustic soda,<a href="http://en.wikipedia.org/wiki/Sodium_hydroxide#cite_note-msd-1" >[2]</a><a href="http://en.wikipedia.org/wiki/Sodium_hydroxide#cite_note-msd2-2" >[3]</a>with the <a href="http://en.wikipedia.org/wiki/Molecular_formula" title="Molecular formula" class="mw-redirect" >molecular formula</a> <a href="http://en.wikipedia.org/wiki/Sodium" title="Sodium" >Na</a><a href="http://en.wikipedia.org/wiki/Hydroxide" title="Hydroxide" >OH</a> is a highly <a href="http://en.wikipedia.org/wiki/Caustic(substance)" title="Caustic (substance)" class="mw-redirect" >caustic</a> metallic<a href="http://en.wikipedia.org/wiki/Base(chemistry)" title="Base (chemistry)" >base</a> which is a white solid available in pellets, flakes, granules, and as a 50% <a href="http://en.wikipedia.org/wiki/Saturated_solution" title="Saturated solution" class="mw-redirect" >saturated solution</a>.

It is soluble in <a href="http://en.wikipedia.org/wiki/Water" title="Water" >water</a>, <a href="http://en.wikipedia.org/wiki/Ethanol" title="Ethanol" >ethanol</a> and <a href="http://en.wikipedia.org/wiki/Methanol" title="Methanol" >methanol</a>. This <a href="http://en.wikipedia.org/wiki/Alkali" title="Alkali" >alkali</a> is<a href="http://en.wikipedia.org/wiki/Deliquescent" title="Deliquescent" class="mw-redirect" >deliquescent</a> and readily absorbs <a href="http://en.wikipedia.org/wiki/Moisture" title="Moisture" >moisture</a> and <a href="http://en.wikipedia.org/wiki/Carbon_dioxide" title="Carbon dioxide" >carbon dioxide</a> in<a href="http://en.wikipedia.org/wiki/Air" title="Air" class="mw-redirect" >air</a>.

Sodium hydroxide is used in many industries, mostly as a strong<a href="http://en.wikipedia.org/wiki/Chemical_compound" title="Chemical compound" >chemical</a> <a href="http://en.wikipedia.org/wiki/PH" title="PH" >base</a> in the manufacture of <a href="http://en.wikipedia.org/wiki/Wood_pulp" title="Wood pulp" class="mw-redirect" >pulp</a> and <a href="http://en.wikipedia.org/wiki/Paper" title="Paper" >paper</a>, <a href="http://en.wikipedia.org/wiki/Textile" title="Textile" >textiles</a>,<a href="http://en.wikipedia.org/wiki/Drinking_water" title="Drinking water" >drinking water</a>, <a href="http://en.wikipedia.org/wiki/Soap" title="Soap" >soaps</a> and <a href="http://en.wikipedia.org/wiki/Detergent" title="Detergent" >detergents</a> and as a <a href="http://en.wikipedia.org/wiki/Drain_cleaner" title="Drain cleaner" >drain cleaner</a>.

Worldwide production in 2004 was approximately 60 million<a href="http://en.wikipedia.org/wiki/Tonne" title="Tonne" >tonnes</a>, while demand was 51 million tonnes.<a href="http://en.wikipedia.org/wiki/Sodium_hydroxide#cite_note-Ullmann-3" >[4]</a> Although molten sodium hydroxide also possesses similar properties, the high temperature required limits applications.

Sodium hydroxide is used in the home as a <a href="http://en.wikipedia.org/wiki/Drain_cleaner" title="Drain cleaner" >drain cleaning agent</a> for clearing clogged drains, usually in the form of a dry crystal or as a thick liquid gel. Sodium hydroxide <a href="http://en.wikipedia.org/wiki/Saponification" title="Saponification" >saponifies</a> the triglycerides found in fat into water soluble fatty acid salts and <a href="http://en.wikipedia.org/wiki/Hydrolysis" title="Hydrolysis" >hydrolyzes</a> the amide bonds in <a href="http://en.wikipedia.org/wiki/Protein" title="Protein" >protein</a>, such as those found in hair. These reactions are sped by the <a href="http://en.wikipedia.org/wiki/Exothermic" title="Exothermic" >heat generated</a> when sodium hydroxide and the other chemical components of the cleaner dissolve in water. Such drain cleaners and their <a href="http://en.wikipedia.org/wiki/Acid" title="Acid" >acidic</a> versions are highly caustic and should be handled with care.

Sodium hydroxide is used in some <a href="http://en.wikipedia.org/wiki/Relaxer" title="Relaxer" >relaxers</a> to <a href="http://en.wikipedia.org/wiki/Straighten_hair" title="Straighten hair" class="mw-redirect" >straighten hair</a>. However, because of the high incidence and intensity of chemical burns, manufacturers of chemical relaxers use other alkaline chemicals in preparations available to average consumers. Sodium hydroxide relaxers are still available, but they are used mostly by professionals.

A solution of sodium hydroxide in water was traditionally used as the most common paint stripper on wooden objects. Its use has become less common, because it can damage the wood surface, raising the grain and staining the colour.

Food uses of sodium hydroxide include washing or chemical peeling of <a href="http://en.wikipedia.org/wiki/Fruits" title="Fruits" class="mw-redirect" >fruits</a> and <a href="http://en.wikipedia.org/wiki/Vegetables" title="Vegetables" class="mw-redirect" >vegetables</a>, <a href="http://en.wikipedia.org/wiki/Chocolate" title="Chocolate" >chocolate</a> and <a href="http://en.wikipedia.org/wiki/Cocoa_mass" title="Cocoa mass" class="mw-redirect" >cocoa</a> processing, <a href="http://en.wikipedia.org/wiki/Caramel_coloring" title="Caramel coloring" class="mw-redirect" >caramel coloring</a> production, <a href="http://en.wikipedia.org/wiki/Poultry" title="Poultry" >poultry</a> scalding, <a href="http://en.wikipedia.org/wiki/Soft_drink" title="Soft drink" >soft drink</a> processing, and thickening <a href="http://en.wikipedia.org/wiki/Ice_cream" title="Ice cream" >ice cream</a>.

<a href="http://en.wikipedia.org/wiki/Olive" title="Olive" >Olives</a> are often soaked in sodium hydroxide for softening; or, if soaked longer, for transformation into <a href="http://en.wikipedia.org/wiki/Black_olives" title="Black olives" class="mw-redirect" >black olives</a>.

<a href="http://en.wikipedia.org/wiki/Pretzel" title="Pretzel" >Pretzels</a> and <a href="http://en.wikipedia.org/wiki/Germany" title="Germany" >German</a> <a href="http://en.wikipedia.org/wiki/Lye_roll" title="Lye roll" >lye rolls</a> are glazed with a sodium hydroxide solution before baking to make them crisp. Owing to the difficulty in obtaining food grade sodium hydroxide in small quantities for home use, <a href="http://en.wikipedia.org/wiki/Sodium_carbonate" title="Sodium carbonate" >sodium carbonate</a> is often used in place of sodium hydroxide.<a href="http://en.wikipedia.org/wiki/Sodium_hydroxide#cite_note-Hominy-18" >[19]</a>

Specific foods processed with sodium hydroxide include:

<ul >

<li >The <a href="http://en.wikipedia.org/wiki/Pinoy" title="Pinoy" >Pinoy</a> or Filipino dessert (kakanin) called kutsinta uses a bit of lye water to help give the rice flour batter a jelly like consistency.</li>

<li >A similar process is also used in the kakanin known as pitsi-pitsi or pichi-pichi (pit-chi-pit-chi) except that the mixture uses grated <a href="http://en.wikipedia.org/wiki/Cassava" title="Cassava" >cassava</a> instead of rice flour.</li>

<li >The <a href="http://en.wikipedia.org/wiki/Scandinavia" title="Scandinavia" >Scandinavian</a> delicacy known as <a href="http://en.wikipedia.org/wiki/Lutefisk" title="Lutefisk" >lutefisk</a> (from lutfisk, "lye fish").</li>

<li ><a href="http://en.wikipedia.org/wiki/Hominy" title="Hominy" >Hominy</a> is dried <a href="http://en.wikipedia.org/wiki/Maize" title="Maize" >maize</a> (corn) kernels reconstituted by soaking in <a href="http://en.wikipedia.org/wiki/Lye" title="Lye" >lye</a>-water. These expand considerably in size and may be further processed by frying to make <a href="http://en.wikipedia.org/wiki/Corn_nuts" title="Corn nuts" class="mw-redirect" >corn nuts</a> or by drying and grinding to make <a href="http://en.wikipedia.org/wiki/Grits" title="Grits" >grits</a>.<a href="http://en.wikipedia.org/wiki/Nixtamal" title="Nixtamal" class="mw-redirect" >Nixtamal</a> is similar, but uses <a href="http://en.wikipedia.org/wiki/Calcium_hydroxide" title="Calcium hydroxide" >calcium hydroxide</a> instead of sodium hydroxide.</li>

<li >Sodium hydroxide is also the chemical that causes gelling of egg whites in the production of <a href="http://en.wikipedia.org/wiki/Century_egg" title="Century egg" >Century eggs</a>.</li>

<li >German <a href="http://en.wikipedia.org/wiki/Pretzel" title="Pretzel" >pretzels</a> are poached in a boiling <a href="http://en.wikipedia.org/wiki/Sodium_carbonate" title="Sodium carbonate" >sodium carbonate</a> solution or cold sodium hydroxide solution before baking, which contributes to their unique crust.</li>

<li >Lye-water is an essential ingredient in the crust of the traditional baked Chinese moon cakes.</li>

<li >Most yellow coloured <a href="http://en.wikipedia.org/wiki/Chinese_noodles" title="Chinese noodles" >Chinese noodles</a> are made with <a href="http://en.wikipedia.org/wiki/Lye" title="Lye" >lye</a>-water but are commonly mistaken for containing egg.</li>

<li >Some methods of preparing olives involve subjecting them to a lye-based brine.<a href="http://en.wikipedia.org/wiki/Sodium_hydroxide#cite_note-19" >[20]</a></li>

</ul>

Lye is a <a href="http://en.wikipedia.org/wiki/Corrosive" title="Corrosive" class="mw-redirect" >corrosive</a> <a href="http://en.wikipedia.org/wiki/Alkali" title="Alkali" >alkaline</a> substance, commonly <a href="http://en.wikipedia.org/wiki/Sodium_hydroxide" title="Sodium hydroxide" >sodium hydroxide</a> (<a href="http://en.wikipedia.org/wiki/Sodium" title="Sodium" >Na</a><a href="http://en.wikipedia.org/wiki/Hydroxide" title="Hydroxide" >OH</a>, also known as 'caustic soda') or historically<a href="http://en.wikipedia.org/wiki/Potassium_hydroxide" title="Potassium hydroxide" >potassium hydroxide</a> (<a href="http://en.wikipedia.org/wiki/Potassium" title="Potassium" >K</a><a href="http://en.wikipedia.org/wiki/Hydroxide" title="Hydroxide" >OH</a>, from hydrated <a href="http://en.wikipedia.org/wiki/Potash" title="Potash" >potash</a>). Previously, lye was among the many different <a href="http://en.wikipedia.org/wiki/Alkali" title="Alkali" >alkalis</a> leached from <a href="http://en.wikipedia.org/wiki/Hardwood" title="Hardwood" >hardwood</a>ashes.<a href="http://en.wikipedia.org/wiki/Lye#cite_note-0" >[1]</a> Today lye is commercially manufactured using a <a href="http://en.wikipedia.org/wiki/Membrane_(selective_barrier)" title="Membrane (selective barrier)" class="mw-redirect" >membrane</a> cell method.

Solid dry lye is commonly available as flakes, pellets, microbeads, and coarse powder. It is also available as solution, often dissolved in water. Lye is valued for its use in food preparation, <a href="http://en.wikipedia.org/wiki/Soap_making" title="Soap making" class="mw-redirect" >soap making</a>, <a href="http://en.wikipedia.org/wiki/Biodiesel" title="Biodiesel" >biodiesel</a> production, and household uses, such as oven cleaner and drain opener.

Sodium Hydroxide (lye)

Attachments