What’s the difference between liquid and powder laundrydetergent? It’s not just the obvious
Published: November 11, 2024 12.22am GMT When shopping for alaundry detergent, the array of choices is baffling. All of the products willlikely get your laundry somewhat cleaner. But what gets the best outcome foryour clothes and your budget? Do you want whiterwhites? Do you need enzymes? And what’s the difference between a powder andliquid detergent? As is often thecase, knowing more about the chemistry involved will help you answer thosequestions. What is a detergent? The active ingredientsin both laundry powders and liquids are “surfactants”, also known as detergents(hence the product name). These are typically charged or “ionic” molecules thathave two distinct parts to their structure. One part interacts well with waterand the other interacts with oils.This useful property allows surfactants tolift grease and grime from fabrics and suspend it in the water. Surfactants canalso form bubbles. Metal saltsdissolved in your water can limit the performance of the surfactants. So-calledhard water contains lots of dissolved calcium and magnesium salts which canreadily form soap scum. Modern laundrydetergents therefore contain phosphates, water softeners and other metal“sequestrants” to stop the formation of soap scum. Phosphates can cause algalblooms in fresh water environments. This is why modern detergent formulationscontain smaller amounts of phosphates. Many products alsocontain optical brighteners. These chemicals absorb ultraviolet light andrelease blue light, which provides the “whiter white” or “brighter colour”phenomenon. Laundry detergentstypically contain fragrances. These aren’t essential to the chemistry ofcleaning, but give the impression the clothes are fresh. Lastly, somelaundry detergents contain enzymes – more on those later. What’s in laundry powder? While detergentsand ingredients to avoid soap scum are the most important components, theyaren’t the most abundant. The main ingredients in powders are salts (likesodium sulfate) that add bulk and stop the powder from clumping. Another common saltadded to laundry powders is sodium carbonate, also known as washing soda.Washing soda (a chemical cousin of baking soda) helps to chemically modifygrease and grime so they dissolve in water. Laundry powders alsofrequently contain oxidising agents like sodium percarbonate. This is a stablecombination of washing soda and hydrogen peroxide. An additive known astetraacetylethylenediamine activates the percarbonate to give a mild bleachingeffect. Chemically, powdershave an advantage – their components can be formulated and mixed but keptseparate in a solid form. (You can usually see different types of granules inyour laundry powder.) View from insidethe washing machine with a man reaching out pulling out clean laundry. Fragrances added tolaundry detergents aren’t essential, but give the impression of clean clothes.Monkey Business Images/Shutterstock What’s in laundry liquid? The main ingredientof laundry liquid is water. The remaining ingredients have to be carefullyconsidered. They must be stable in the bottle and then work together in thewash. These includesimilar ingredients to the powders, such as alkaline salts, metal sequestrants,water softeners and surfactants. The surfactants inliquid products are often listed as “ionic” (charged) and “non-ionic”(non-charged). Non-ionic surfactants can be liquid by default, which makes theminappropriate for powdered formulations. Non-ionic surfactants are good atsuspending oils in water and don’t form soap scum. Liquid detergentsalso contain preservatives to prevent the growth of microbes spoiling themixture. There are alsomicrobial implications for inside the washing machine. Liquid products can’tcontain the peroxides (mild bleaching agents) found in powdered products.Peroxides kill microbes. The absence of peroxides in liquid detergents makes itmore likely for mould biofilms to form in the machine and for bacteria to betransferred between items of clothing. As an alternativeto peroxides, liquids will typically contain only optical brighteners. Liquids do have oneadvantage over powders – they can be added directly to stains prior to placingthe item in the wash. A recent“convenience” version of liquid formulas are highly concentrated detergentpods. Colourful and bearing a resemblance to sweet treats, these products havebeen found to be dangerous to young children and people with cognitiveimpairment. Pods also removethe option to add less detergent if you’re running a smaller load or just wantto use less detergent in general. A colourful green,blue and purple plastic sachet about to be placed in a washing machine. Detergent ‘pods’mainly contain highly concentrated laundry liquid. So, what about enzymes? Enzymes arenaturally evolved proteins included in laundry products to remove specificstains. Chemically, they are catalysts – things that speed up chemicalreactions. Enzymes are namedfor the molecules they work on, followed by the ending “-ase”. For example,lipase breaks down fats (lipids), protease breaks down protein, while amylaseand mannanase break down starches and sugars. These enzymes arederived from organisms found in cool climate regions, which helps them functionat the low temperature of washing water. Running anexcessively hot wash cycle can damage or denature the enzyme structure,stopping them from assisting in your wash. Think of an egg white changing fromtranslucent to white while cooked – that’s protein denaturing. If your detergentcontains enzymes, the washing temperature should be neither too hot nor toocold. As a guide, temperatures of 15–20°C are used in standard laundry tests. Is powder or liquid better? We make consumerchoices guided by performance, psychology, cost, scent, environmentalconsiderations and convenience. It’s worthexperimenting with different products to find what works best for you and fitsyour needs, household budget and environmental considerations, such as havingrecyclable packaging. Personally, I washat 20°C with half the recommended dose of a pleasant-smelling laundry powder,packaged in recyclable cardboard, and containing a wide range of enzymes and anactivated peroxide source. getting your clothes clean. However, laundrydetergent manufacturers don’t always disclose the full list of ingredients ontheir product packaging. If you want moreinformation on what’s in your product, you have to look at the product website.You can also dig a little deeper by reading documents called safety data sheets(SDS). Every product containing potentially hazardous chemicals must have an SDS. Chemistry Chemicals detergent Laundry What's the difference? Before you go …90,000 experts have written for TheConversation. Because our only agenda is to rebuild trust and serve thepublic by making knowledge available to everyone rather than a select few. Jo Adetunji, Editor, TheConversation UK -- You received this message because you are subscribed to the Google Groups "Thatha_Patty" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion visit https://groups.google.com/d/msgid/thatha_patty/1994104454.1412822.1731498160377%40mail.yahoo.com.
