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Ask Dr. Laundry

Ask Dr. Laundry

Bleach Carryover

By Dr. Laundry December 14, 2010

Q. I’m using a bleach containing sodium hypochlorite. I use it mostly for laundry issues and killing the germs rather than whitening. I use it for cleaning my underwear at pre-wash, and then continue washing with detergents as a common washing. The problem is, my washing machine doesn’t rinse after the prewash. It just ejects the water and then takes the detergent in with clean water. As I have read from sources on the internet, when I put sodium hypochlorite and detergent together, sodium hypochlorite reacts with detergent and it destroys some detergent ingredients like enzymes and FWAs. Could the sodium hypochlorite that remains after the prewash react with my detergent? Or does sodium hypochlorite react so well with soils and even with my cotton underwear that if there’s not enough soil for it to react with (or just assume that I’ve put too much bleach), there won’t be any sodium hypochlorite after the prewash ?

I believe from your description that you are using a prewash or presoak cycle before the regular wash. You didn’t indicate whether you have a top loader or HE washer.

For cleaning whites, especially underwear, I recommend that the wash be done in hot water containing detergent and 3/4 cup Clorox® Regular- Bleach. You can also add a presoak/prewash step to enhance the cleaning. So, if your washer doesn’t rinse the presoak solution away, it simply will use any remaining sodium hypochlorite carried into the subsequent wash cycle. If you are using a reduced amount of bleach for the prewash (since it has less water than a regular wash), you probably won’t have much carryover, if any. Actually, some bleach carryover to the main wash should be helpful as the detergent starts to use its ingredients to clean the clothes, the bleach will hasten the breakdown of any remaining soils and stains making them easier for the detergent to remove from the fabric.

While the sodium hypochlorite can react with some of the detergent enzyme and brighteners, using a bleach dispenser for the main wash addition will delay the bleach addition and minimize this potential reaction. You might consider adding some extra Clorox® Regular- Bleach for the main wash.