This week, a reader writes with a question about towels that tends to come up more often in summer, and can plague both bath and beach towels equally:
I heard an interview in which you talked about eliminating that musty smell in towels … it had something to do with soap residue. I bought your book (which I love) thinking that it would be in there, but, alas, it isn’t and recently I’ve been noticing a musty odor in some of my towels. So I need help!
Wait, it seems UNPOSSIBLE that I wrote an entire book and didn’t mention the musty towel thing. It’s so very common! And the science behind it is kind of cool!! And the solution is super easy!!! [checks manuscript] Hmm … well, there is something in there about towels that have mildewed from being left in the washer, so in fairness to me the solution is there, if not the explanation of the precipitating incident.
So let’s start with the reason why otherwise clean towels may smell musty, either just out of the dryer (less common) or after one use (very common). The culprit is generally that you have used too much laundry detergent! Yes, that’s all.
What happens is this: Washing machines have a set rinse cycle, and if you use too much detergent not all the soap residue will be, well, rinsed away during that set cycle. The machine doesn’t detect the absence of soap in order to know when to stop rinsing, it just stops rinsing at the same old time it always stops rinsing. Then, the towel all still filled up with soap residue, you go to use it and the combination of the water that you’ve dried from yourself plus the soap lingering within the towel makes a very inviting home for mildew to put down roots. Mildew, you see, needs food and water to thrive, and soap (as well as, ewww, your dead skin that gets transferred from self to towel when you dry off) serves as food. So! Now you know why it’s happening and we can move right along to what to do about it, and how to prevent it from happening in the future.
The first thing to do is to wash the towels again, but in a way designed to essentially strip away all that product buildup. To do this, you’ll want to break yourself of two bad but common and understandable laundry habits; the first is overusing detergent and the second is overstuffing the washing machine. So! Use a HALF DOSE of detergent. Which means you have to go find out what a FULL DOSE actually is because it is almost never “filling the cap or scoop up all the way up” I’m sorry to tell you. It’s not your fault that you do that! It is actually very specifically the fault of the detergent manufacturers, but that’s another rant for another day. This is also not the best time to use detergent pods, since you cannot easily control dosage; stick with a liquid or powder detergent for this operation.
Of course, in order to know how much detergent to use (or not to use, in this case) you need to understand how load sizes are measured. Here’s some laundry math for you: Load size is expressed in one of two ways; the first is by how full the drum of the machine is, and the other is by weight.
Medium: ½ full, or 8-10 lbs.
Large: ¾ full, or 10-12 lbs.
Extra-large: Full, or 12-15 lbs.
For this purpose, it’s important the drum is no more than ¾ full — this isn’t the time to do an extra-large load, as you’ll want to make sure that there is plenty of room for water to make contact with the towels, flushing away all that buildup. Then, it is also a good idea to add 1 cup of white vinegar to the wash cycle, which will also help to break down some of the buildup, as well as eliminate much of the bacteria that’s causing the odor in the first place. That’s all! When the towels come out, they may smell vaguely of vinegar, but that smell will dissipate right quick once they go through the dryer.
But let’s say you hate the smell of white vinegar so much you can’t even stand to pour it in the washer. No problem! Skip it in favor of another option such as:
- Baking soda or Borax;
- An odor eliminating laundry booster like Zero Odor or Funk Away, which is used in addition to regular laundry detergent;
- A detergent with odor eliminating boosters built in, like Tide Sport or Sport Suds;
- Our old friend Dr. Bronner’s.
Just remember with any of these products, be they boosters or detergents with odor eliminating properties, to only use a half dose when treating mildew-smelling towels because of buildup. Then, going forward, be mindful of using the right detergent dosage based on load size so as not to cause the problem all over again.
Also as a reminder, opt for dryer balls when drying towels and do not use fabric softener — neither the liquid stuff nor the dryer sheet stuff — on your them, as fabric softener is the Devil’s own laundry booster. Also it leaves behind a coating that makes towels less absorbent.