pH
Refer to previous discussions about pH and its effect upon clothes fabrics, soil and plant available nutrients. The favourable range of pH for biological purposes is 5-9.
The laundry liquids were mixed at the recommended dose for both front loaders and top loaders. There were only two products within the range tested that were specifically for front loaders (block letters).
The liquid detergents were mixed with deionised water (equivalent to very clean rainwater) which has a starting pH about 5, hence products that had very little effect upon wash water pH will have low pH results. You need to take into account the starting pH of the water, but you cannot just add the numbers together because pH is not a linear measurement. Unfortunately because of the high variability in pH of town water supplies, it is not possible to give examples of the changes.
Figure LF1-pH Effect of mixing recommended dose of liquid laundry detergent for a front loaders with water equivalent to rainwater quality.
Figure LT1-pH Effect of mixing recommended dose of liquid laundry detergent for a top loaders with water equivalent to rainwater quality.
Assessment
The pH of the liquid laundry products when mixed at the recommended dose are mostly within the acceptable range for biological systems (5-9 pH), although the products with pH around 10 are highly alkaline. When compared with the powdered products, the liquids offer a less hazardous option for washing delicate fabrics.