Slios Bruguaine

Lye Part 4: Saponification  To read the first post about the history of lye, see: Lye Part 1 . To read about potash lye, see Lye Part 2 , and for soda ash lye, see Lye Part 3 . Saponification Saponification is the chemical reaction between an alkaline substance and a fatty acid, making soap. Alkaline detergents can be very harsh and corrosive. Saponification lessens their cleansing ability to some extent, but it also makes them safer to use. A strong lye can burn the skin from brief contact, and even a weak lye will dry and irritate the hands in the time it takes to wash a bunch of laundry or dishes. Soap preserves enough cleansing power to aid in washing, but it is mild and unlikely to bother any but the most sensitive skins. In some cases, extra fat is added to soap so that is soothing or moisturizing—a far cry from the lye that made it. Chemistry of Saponification Saponification is a form of hydrolysis (1) . Fatty acids consist of long chains of hydrocarbons (CH2), so...

Lye Part 3: Soda ash lye  To read the first post about the history of lye, see: Lye Part 1 . To read the previous post on potash lye, see Lye Part 2 . Soda ash lye Soda ash, as opposed to potash, comes from burning very specific vegetable matter—usually plants growing in sodium-rich or salty conditions, such as barilla and seaweed/kelp. It contains sodium carbonate, Na2CO3, also called black ash, washing soda or just soda. It behaves quite noticeably differently from potash lye, and was thus distinguished early on for the production of hard soaps (instead of soft soaps). Soda ash is related to natron (the cleansing salt favored by the Egyptians because it could be dug up locally); natron is a natural mix of sodium carbonate decahydrate (Na2CO3*10 H20) and sodium bicarbonate (NaHCO3, baking soda). Sodium carbonate is a water soluble base that, like potassium carbonate, is capable of saponification on its own, although the process will be incomplete and leave about 10% of ...

Lye Part 2: Potash  To read the first post about the history of lye, see the previous post: Lye Part 1 . Potash lye Potash, in this context, refers specifically to the ashes made by burning woody plants. Ideally, the firewood should come from hardwood species of tree: beech, mulberry, oak, locust, ash, elm, maple, birch, etc. Fresh potash is basic, typically around 11.6 pH (1) . The ash is then soaked in water and filtered out, leaving a weak lye; this process is called leaching. Repeated leachings through fresh ashes can add to the strength of the lye, or the weak lye can be simmered to quickly evaporate away water and concentrate the lye. Potash also refers to the chemical compound, potassium carbonate, which traditionally came from hardwood ashes. In older literature, potash could also refer to dehydrated potassium-hydroxide (the ashes left in the pot after hardwood ash leachate is boiled off). Since all three substances will be discussed here, potassium carbonate and p...

Lye Part 1: History  Definition Lye refers to an alkaline metal, such as potassium or sodium, dissolved in water (H2O). It can come from a variety of sources, but historically it was collected by filtering water through plant ashes, especially hardwood ashes (potash) or the ash of certain salt-tolerant plants such as barilla and sea kelp. Lye is basic, or alkaline, meaning the solution has a high pH (above 7). The liquid has a metallic taste and a slippery feel to the touch. However, touching lye can cause severe chemical burns, especially when concentrated! Even a mild lye solution should be rinsed off of the skin quickly. Leaving a base in contact with skin results in the chemical reaction between the base and the fatty acids (natural oils) of the skin. In addition to stripping the oils from the skin, this reaction also produces heat. At the mildest level, this makes for dry, irritated skin; at worst, it can cause serious cellular damage, with resultant blistering and pa...