Lye Part 1

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 pain. Particular care should be taken to avoid ingesting, inhaling or splashing the eyes with any variety of lye. Flushing with running water and removing the lye by scrubbing are FAR safer options than attempting to “neutralize” the base with an acid like vinegar, as popularized by some movies. The reaction between lye and an acid is exothermic; pouring acid onto the existing lye burn will increase the heat of the reaction and worsen the burn.

As a cleanser, lye has seen use from prehistoric times. Even the hardwood ashes themselves, containing only small amounts of lye, can be used as an abrasive scrubbing cleanser for dirty dishes by a campfire. This works because lye is a surfactant—a substance that reduces the surface tension of the liquid in which it is dissolved. In other words, lye makes it easier for water molecules to reach and bond to dirt particles, helping carry them away dirt during washing. This means that lye works as a detergent on its own, with no other ingredients needed.

As a detergent, lye can clean laundry, hair, floors, dishes, wool fleeces, hides and many other domestic items; the concentration of lye can be varied according to the intended use (laundry-strength lye will not be kind to the scalp if it is used as shampoo).

Lye can be turned into a gentler, safer cleaning product by making use of its chemical reaction with fats. When exposed to a fatty acid, lye reacts by breaking the 'tails' off of the fatty acid chains, and then bonds itself to the main fat molecules. This reaction is known as “saponification” or, colloquially, making soap. For more on saponification, see Lye Part 4.

Prehistoric Evidence

The usefulness of lye as an alkaline, caustic liquid has been understood for millennia. Along with hydrated lime and fermented urine, lye is one of the simplest chemicals known to man for the purpose of dehairing a hide, an essential step for making any kind of leather.

Primitive buckskinning typically uses wood-ash drippings, or potash lye, both for the cleansing of grease out of a hide and for removing the hair. This is because wood ashes can be spread dry upon a hide, which can then be rolled up and carried—an important point if a tribe is nomadic and cannot tote around a heavy tub or bucket in which to soak the skin. The lye, used thus, slowly penetrates the cells of the hide, swelling them and causing the follicles to release the hairs; also, the lye in the ashes prevents most bacterial decay of the skin, even if the hunter carries it for weeks in warm weather. This stone-age chemistry was likely understood globally, long before even the Neolithic period, but of course, evidence is sparse, and speculation must rely upon more modern primitive cultures for analogs (a comparison fraught with baseless assumptions).

The use of lye as a cleanser, likewise, must merely be guessed at prior to civilization, when direct evidence begins to appear (such as the presence of ashes at laundry infrastructures in Minoan Crete). It is not a great step to go from dehairing and rinsing a hide with ashes, to begin washing finished hides, and then other things, with ashes. Ashes work as an abrasive and as a source of lye, making them particularly helpful in cleaning up after cooking or in getting grease out of dirty hair.

Soap may have been in use unintentionally as early as the start of the Iron Age, when iron pots came into common use for cooking. Seasoning an iron pot with fat prevents rust and creates a non-stick surface (the polymerized oils form a plastic layer, coating the metal below), but excess grease left in the pot will go rancid or rot. Washing a greasy pot with ashes would result in mixing water, lye, and fat—the necessary three ingredients for soap-making. It would only require some observant dish-washer to notice that their hands were not as irritated when washing a greasy pot as when washing a bare metal pot.

In the absence of written documentation, however, linguistics can sometimes offer clues as to the origin, or at least timing, of a new technology. For example, before the invention of e-mail, there was no word for electronic messages sent online; the use of the technology preceded the need for a word to describe that technology. Therefore, it is useful to note that the Proto-Indo-European language has an etymon (root word) for lye: “ƙormno-” or “corrosive liquid, lye” (1). This suggests a knowledge of lye, and the need for a distinct word for it, as early as the Late Neolithic or Early Bronze Age, between 4,500 BCE and 2,500 BCE.

Furthermore, the Proto-Indo-European (PIE) etymon “lou-” provides the basis for words meaning “to wash” in the Indo-European languages (1). In many of them (English, Old High German, German, Norwegian, and Swedish) this root came to mean “lye,” as well as “to lather.” Indeed, the Old English word “lēaðor,” meaning lather, has barely changed its spelling over the years, while the Old English word for lye, “lēag,” is not greatly altered. In Latin and Greek, the root became words like “lavare” (and many other forms), which can be recognized in English derivative words like “lavatory.”

Among the Germanic languages, the verb “būchen” translates to, “to wash out with lye” (2). Thus, “bouken” in Old English meant “to soak in lye” and in Frankish, “būkōn” meant “to wash, to soak.” The modern English derivative, “buck” (3), refers to a lye bath used to dehair a hide for leatherwork; a buckskin is a skin that has been “bucked,” not a reference to the sex of the animal.

This linguistic overview is necessarily vague and can only indicate the cultural knowledge of the substance, lye, and that it was associated with cleaning. Interestingly, the PIE etymon for lye (ƙormno-) also means suffering and pain—an appropriate association for caustic liquid, and probably not coincidental. Thus the language preserves evidence of a basic (pun intended) understanding of lye and its properties dating to around 5,000 years ago, if not more.

Early Historic Evidence

Written evidence of alkaline cleaning products comes from a multitude of sources, starting as early as an Akkadian parody of wisdom literature, written in Ur sometime between 1,900-1,600 BCE, called “At the Cleaners” (4). Here, a pompous scribe condescendingly dictates his elaborate instructions for cleaning his finely woven wrap, and then low-balls the aślāku (laundry cleaner/fuller), who rejects the insulting offer and scoffs at him, telling the scribe that he can go clean his own clothes and get a skin rash on his own hands in the process. According to Stefan Zawadzki, who studied the evidence for textile industries in ancient Babylonian texts, the alkali used for bleaching laundry was sometimes produced from the ashes of the tamarisk plant (5)—he cites receipts by an ana zukkú (professional linen bleacher) and an aślāku for tamarisk to create their laundry cleaning powders. He likewise demonstrates that the laundry specialists would cook alkali and oil together in water, dating the knowledge and use of saponification to the 3rd millennium BCE.

As a side note, the ancient Egyptians were clearly fastidious and valued cleanliness, daily bathing, bleaching and washing laundry, and the use of bodily cleansers, perfumes and oils. However, their written evidence seems to show a clear preference for natron, a naturally abundant chemical that could be dug up from local salt lakes and served numerous purposes, especially in laundry, bathing and embalming. Lye appears not to have found favor in Egypt; speculatively, perhaps because their hot climate did not encourage prolonged heating fires very year, and thus they did not generate much wood ash.

The use of alkaline ash was clearly known to the Jews in the 1st millenium BCE, who may have learned from the Phœnicians. The Book of Isaiah, in the Tanakh, mentions lye in the context of metalworking in chapter 1 verse 25: “purge away your dross as with lye, and remove all your tin.” This book was written sometime between 740 and 686 BCE. Isaiah here demonstrates understanding of alkaline plant ashes in the smelting and refining of metal. The word in use, “kabor,” may refer to lye, or alkali, or potash, or the basic ashes of the borith herb (6). Centuries later, the Mishnah of the Talmud (written between 70-200 CE) names “seven substances... [that clean] a stain: tasteless spittle, the liquid of crushed beans, [fermented] urine, natron, lye, cimolian earth, and lion's leaf” (7). Human saliva (before a meal) contains enzymes that break down organic stains; a paste of bean starch can absorb grease and peel it away; fermented urine provides urea, enzymes and ammonia; natron, cimolian earth (a clay similar to fuller's earth), and lion's leaf (a plant with alkaline roots), were all popular laundry cleansers of the region. Obviously, lye was already in common enough usage to need no other explanation, and was correctly lumped among other alkaline detergents.

Roman texts likewise refer to washing using lumps of prepared alkali and hot water, particularly to degrease wool fleece and textiles. This, according to Pliny the Elder (Vol 9 Ch. 62), was a necessary step before dyeing could occur (8). The 1st millenium BCE Greek term for lye, κουία, can also be translated to, “to sprinkle with ashes,” and the Latin words lixa, or lixivium, both mean lye (9) and can be found in contexts of cleaning as well as medicine (Pliny claims that Varro indicated drinking lye to sooth an upset stomach). Varro writes in the 1st century BCE, “when I was in command of the army in the interior of Transalpine Gaul near the Rhine, I visited a number of spots... where they had no salt, either mineral or marine, but instead of it used salty coals obtained by burning certain kinds of wood” (10). Likely, these 'salty coals' may actually be ashes, based upon the prevalence of ash-preserved meats, fish and cheeses in northern Europe, attested to later in the Medieval Period (ex. lutfisk).

From Pliny's Natural History also comes the first known written mention of soap by name; in Book 28, Chapter 51, he says, “this substance is prepared from tallow and ashes, the best ashes for the purpose being those of the beech and yoke-elm: there are two kinds of it, the hard soap and the liquid, both of them much used by the people of Germany” (8). Pliny wrote this around 77 CE, and claimed that soap had been invented in Gaul. Clearly soap-making was already fairly advanced at the time he wrote this, since the simplest soap (from potash) is invariably liquid; making a hard soap requires extra steps, or special ashes.

Mentions of lye and soap become more common as the expansion of the written record continues. Thoeodori Prisciani, writing in the 4th century CE, mentions Gallic soap (that soap which comes from Gaul and is used for washing the head), as well as naming the profession of soap-maker (saponarius) (11). The Alphabet of Galen, a work that was misattributed to Galen but likely dates, in truth, to between the 4th and 6th centuries CE (12), gives details on soap of the period. The author states, “soap is made by cooking beef, she-goat, or wether fat [tallow], mixed with lye and quicklime. We judge the best soap to be Germanic, for it is the purest and the creamiest; after this ranks Gallic soap. All types of soap can severely loosen and remove all filth from the body and from clothing” (12). In the deed records of Ravenna, a saponarius named Isaac purchased a share in a farm in the year 541 (13), showing that the soap-making profession had now migrated into Italy.

Around 700 CE, in a text from the Early Medieval Anglo-Saxon church called Paenitentiale Theodori, the use of lye for personal hygiene comes up in a description of Greek and Roman customs. The author states that they permit the use of lye for foot-washing even on the Sabbath (a rest-day, when most labor was prohibited), though he notes that this is a Greek, not a Roman, tradition (14). At the end of the 8th century, Charlemagne instructed his stewards in the management of his estates with a document detailing rules, materials and record-keeping. This document includes several mentions of soap, wax, tallow and oil allotments (every steward is to receive an allotment of eight sextaria of soap per day), as well as referring to professional soap-makers as good craftsmen that should live on his estates (15).

The uses of lye and soap are, from this point on, well-attested, and sources become too numerous to list in a brief overview. However, since this blog specifically focuses on Irish culture and technology, it is time to zoom in on the evidence for lye in the context of Ireland.

History of Lye in Ireland

Prehistoric Ireland has all of the indicators of a civilization that understood the uses of ash in their crafts: they practiced coppicing of hardwoods; they burned wood in their indoor hearths and dug out the ashes regularly; they made glass beads; they dehaired hides in order to make oil-tanned or leather goods; and they cleaned, dyed, and fulled wool textiles. All of these industries can be associated with potash production or use, although this is of course circumstantial at best. The Irish did have excellent woodworking and coopering techniques, so that barrels, vats, troughs and tubs were readily available by the Iron Age, making the leaching of ash lye very practicable for them.

Prehistoric material evidence for the use of lye in Ireland is as sparse as elsewhere, of course, so linguistic sources can again provide some clarity. The Proto-Celtic etymon, “*stleki-” or “lye” (related to the etymon, “*sterk-” meaning, “dung, excrement, urine”) (16), evolved into the Old Irish word, “sléic,” meaning “potash, a personal detergent, or lye” (17). This demonstrates the knowledge of the substance, lye, in the migrating culture before the native Irish even arrived in Ireland (see Insular, not Celtic). Once they had settled in Ireland, about 4,000 years ago, the linguistic mutation of the word in Old Irish clearly associates lye with washing the person, long before the historical period.

Early Irish written sources provide lots of detail about bathing habits. Ireland, in the Early Medieval Period, had a culture that highly valued beauty and cleanliness—often equating the two, and in some stories, showing that they were interchangeable, when ugly characters transform into stunning beauties by taking a special bath. Bathing was a standard part of their daily practices, an expected norm for both hospitality and the care for dependents. Guests could actually sue a host if they did not receive a hot bath and a linen towel after their travels; neglecting the bath was as serious as neglecting to offer adequate food and drink and shelter. Legal obligations likewise extended to a person harmed by another person; the one who committed the violence owed the injured party a period of support and care, until they healed, that included food, shelter and baths. The legal tract Betha Crolige requires that invalids be provided with a bed, a doctor, and regular baths (18). The Triads of Ireland mark three preparations that indicate a good man's house: ale, a bath for the whole body, and a large fire (18). Old Irish even has a specific word for washing the whole body, “fothrucud,” distinguished from washing just the head and hair, or hand-washing or foot-washing.

Topographia Hiberniae f.28v

The upper and middle classes of Ireland were expected to bathe their whole bodies, daily, in hot water (except on the Sabbath, after Christianization). This occurred in large bath tubs, called “dabach fothraicthe,” which were round, stave-built vats bound by wooden or metal hoops, large enough to sit and soak in. The staves could be of yew or oak, according to textual evidence, while wooden hoops could be yew, or willow (18). Evidence from Lagore Crannog (7th - 10th cen) supports the presence of large stave-built vats: one extant remnant showed that the vat it came from was 76.8cm (30”) in diameter at the bottom, and the staves, 64 cm (25”) in height. Others fragmentary vats, from Ballinderry Crannog, confirm these dimensions (18). Bath water was heated by transferring hot stones into the vat, one stone at the start and then one per person; the water could be used successively if multiple people needed to bathe in the same household, and the bathing order went by social status. The stones were removed after the bath, and the water dumped out every evening. A mark of a slovenly household was to have the bath tub still full of water the next morning (18). Likewise, keeping water overnight in the foot bath (a separate tub used only for that purpose) was prohibited. The water would also sometimes be dumped between groups of users; some traditional sources suggest that women bathed separately, or that the bath water for men should not be used to wash women and vice versa.

Irish bathers do not seem to have used soap until after the Norman Conquest, but alkaline detergents were clearly in use. Both stale urine and ash lye appear in the written record in cleansing contexts, but lye in particular seems to be associated with hair-washing. The very word for washing the head, “folcud,” translates also to “lye.” Ashes from the ash tree (cu folcadh fuindseand) were preferred for making hair-wash: “put the ashes in a lye made of ashtree ash... wash the head in it” (18). After washing the hair, a person was expected to wash their hands with clear water—suggesting that the lye was sufficiently strong that it should not be left on sensitive skin for long.

Ashes made from seaweed were valued, separately, for their use in curing meat; “lúaith” means ash, and is specifically not assigned a fine (a legal value) under early Irish property law, but sea-ash, “mur-luaith,” is not exempt. Murluaith was evidently stored in sacks and used in preserving joints of beef. The burning of seaweed specifically to generate murluaith remained in practice in the 1600's, in the small coastal islands of the British Isles, and these seaweed ashes were still used at that time for curing cheese and fish, etc. (18)

Soap-makers existed as a profession in Ireland after the Normans invaded in the late 1100's. By 1213, a saponarius lived and worked his trade in Dublin. Later, the soap-ash industry became a commercial use for waste wood and weed burning in Irish fields. Imports of hard soap from the Continent became an economic norm by the 1500's (although, probably only for the wealthy English landlords and urban residents in Ireland, and not for the typical Irish). Lye and urine remained the standard cleansers in poorer, rural Ireland, especially for laundry and for the fulling of wool cloth. (18)

To read about potash lye, see Lye Part 2.

Sources:

1) Indo-European Lexicon: Pokorny Master PIE Etyma (adapted from Pokorny, Julius. Indogermanisches Etymologisches Wörterbuch. Bern, Francke, 1959.). Linguistics Research Center, University of Texas at Austin. <lrc.la.utexas.edu/lex/master>

2) Wiktionary etymology. <en.m.wiktionary.org/wiki/reconstruction:proto-germanic/būkōną>

3) Bailey, Nathan. An Universal Etymological English Dictionary. J. Buckland et al, 1773.

4) Wasserman, N. “Treating Garments in the Old Babylonian Period: “At the Cleaners” in a Comparative View.” Iraq, 75, 2013. p. 255-277

5) Zawadzki, Stefan. Garments of the Gods: Studies on the Textile Industry and the Pantheon of Sippar According to the Texts from the Ebabbar Archive, Volume 1. Saint-Paul, 2006. p.61

6) Barnes, Albert. Notes: Critical, Explanatory, and Practical on the Book of the Prophet Isaiah. Crocker & Brewster, 1840. p.114

7) Babylonian Talmud: Tractate Niddah. Translated by Rabbi Michael L. Rodkinson, 1901.

8) Pliny the Elder. The Natural History. Translated by John Bostock, H.T. Riley. Taylor and Francis, London, 1855.

9) Gaspa, Salvatore; Michel, Cźcile; Nosch, Marie-Louise. Textile Terminologies from the Orient to the Mediterranean and Europe, 1000 BC to 1000 AD. Zea Books, Lincoln, Nebraska, 2017. p.27

10) Varro, Marcus Terentius. Delphi Complete Works of Varro (Illustrated). Delphi Classics, 2017.

11) Priscianus, Theodorus. Euporiston: Libri III. Lipsiae, 1894. p.10

12) Everett, Nicholas. The Alphabet of Galen: Pharmacy from Antiquity to the Middle Ages. University of Toronto Press, 2012. p.347

13) Penzl, Herbert. “Names and Historical Germanic Phonology: the Bilingual Sixth Century Ravenna Deeds.” Journal of Onomastics, Vol 25, No 1, 1977. p. 8-14

14) Medieval Handbooks of Penance. Translated by John Thomas McNeill, Helena Margaret Gamer. Columbia University Press, 1990. p. 206

15) Loyn, H.R., J. Percival. The Reign of Charlemagne: Documents on Carolingian Government and Administration. London, 1975. p.64-73

16) Matasovic, Ranko. Etymological Dictionary of Proto-Celtic. Brill, Leiden, The Netherlands, 2009.

17) Electronic Dictionary of the Irish Language. 2013. <dil.ie>

18) Lucas, A. T. “Washing and Bathing in Ancient Ireland.” Journal of the Royal Society of Antiquaries of Ireland, Vol 95, No 1, 1965. p. 65-114