• Skip to main content
  • Skip to secondary menu
  • Skip to primary sidebar
  • Skip to footer
  • Become a Premium Member
  • About

Road Bike Rider Cycling Site

Expert road cycling advice, since 2001

  • Pinterest
  • Facebook

Sign up for our informative, free weekly email newsletter. (Always easy to unsubscribe.)

  • Bikes & Gear
  • Training & Health
  • Reviews
  • Cycling Ebooks
    • Ebooks Training
    • Ebooks Skills
    • E-Articles Training
    • E-Articles Nutrition
  • Member Area
  • Newsletter

Tom’s Tip For Keeping Bottles From Growing Mold

Jim’s Tech Talk

By Jim Langley

My Santa Cruz County Cycling club mate and riding buddy Tom Pennello told me this cool tip last week and he gave me permission to share it with you. In his own words,

I almost always ride with something in my primary bottle (a plastic CamelBak Podium bottle). Typically it’s a Nuun tablet, or on a longer ride, Gatorade. Any second bottle is water and I transfer it to the first when needed, adding a tablet or powder packet.

Both Nuun and Gatorade encourage the appearance of little black spots of growth (mold?) in the bottom of the bottle. They hold fast and I’ve had to use a butter knife to scrape them off periodically.

Vitamin C is used as a preservative in various products, so I decided to try it. I fill the bottle half-way, add a little less than a 1/4 teaspoon of Vitamin C powder, shake, squirt a little through the top, and let the bottle sit with the infused water in it.

Behold, no more spots. The bottom of the bottle remains clean.I do this for the bottle any day I’m not riding, or after 2 consecutive days of riding.

The power I use is just Vitamin C — e.g., no sugar added to make it a Vitamin C drink.

This is what I am using (just over $9 for 8 ounces right now: https://www.amazon.com/gp/product/B00028LX1U/

vitamin c bottle

Thanks very much Tom! Readers, we’re always looking for great cycling tips like Tom’s. Send them in when you have them and we’ll run the best ones.


Jim Langley is RBR’s Technical Editor. A pro mechanic & cycling writer for more than 40 years, he’s the author of Your Home Bicycle Workshop in the RBR eBookstore. Tune in to Jim’s popular YouTube channel for wheel building & bike repair how-to’s. Jim’s also known for his cycling streak that ended in February 2022 with a total of 10,269 consecutive daily rides (28 years, 1 month and 11 days of never missing a ride). Click to read Jim’s full bio.

Reader Interactions

Comments

  1. syborg says

    October 16, 2024 at 12:22 am

    I wonder if citric acid would work too.

  2. Andrea says

    October 17, 2024 at 5:58 am

    I use diluted bleach. I shake the bottle and let it sit for an hour. I then rinse with warm water followed by cold water. It works.

    • Nick Levi says

      October 17, 2024 at 7:03 am

      I also use a few drops of bleach in a clean bottle with twice as may drops of water. I swill around so the dilute touches every surface. Let it sit for 1\2 an hour then squirt it out through the drinking spout. After another half an hour rinse the bottle and lid thouroghly, et voila as new!

    • Judi says

      October 17, 2024 at 8:03 pm

      Ditto
      Bleach and hot soapy water. Rinse well.
      Also take apart the cap if you can as mold etc hides in those little crevices.

  3. Brian Nystrom says

    October 17, 2024 at 6:20 am

    Mold cannot survive in an acidic (low pH) environment and many common acidic products can kill it, such as vinegar, lemon juice, and citric acid. Citric acid powder is inexpensive and readily available; it’s used in making wine and candy, among other things. It’s also great for removing rust..

  4. Tom says

    October 17, 2024 at 6:20 am

    Diluted bleach solution (4:1 or 5:1 water to bleach) will easily get rid of mold in your water bottles. Use hot water, can add some soap or not, be sure to let your cap soak with the valve OPEN in that mixture along with the bottle of course for maybe 15 minutes or so. Fill bottle with the solution after the soak, recap, and forcefully squirt solution through the valve. Once mold is gone, thoroughly rinse everything out, squirt hot water through the valve to clear the solution, then rewash if you are really unsure if you got everything out or just let air dry with the valve open.

  5. John Perlman says

    October 17, 2024 at 6:21 am

    I have switched to double walled stainless steel. Still have issue with gunk on the plastic top but none in the bottle. And keeps the drink cold!

    • Quoc says

      October 17, 2024 at 11:06 am

      +1 for stainless steel bottles like Bivo. Better tasting water, Gatorade…whatever. Really…how many more plastic bottles do we need in this world?

    • Judi says

      October 17, 2024 at 8:05 pm

      Love the steel bottles. Just switched this year!

  6. Si litte says

    October 17, 2024 at 7:10 am

    Rinse out with mouthwash after the bleach.

  7. craig says

    October 17, 2024 at 8:11 am

    Specialized Purist bottles have a silica lining which is what glass is. resists mold much longer than normal plastic bottles. And tastes like drinking from a glass, you’ll never switch back.

  8. Jon Stiegel says

    October 17, 2024 at 8:19 am

    On the prevention side, after my ride I rinse the bottles with water then store them in the freezer. Problem solved before it starts!

  9. John Perlman says

    October 17, 2024 at 8:21 am

    and if you like the idea someone else suggested about putting them in the freezer, go ahead and put in a couple inches of water too, then you’ll have a big ice cube in there to keep the drink cold on your next ride. and you won’t hear rattling of regular ice cubes..

    • ad land says

      October 17, 2024 at 10:59 am

      Freezing water in the plastic bottle will erode the plastic = more microplastics in you.

  10. Fred says

    October 17, 2024 at 9:03 am

    Mold is easy to deal with. I use the same products mention in this article from time to time, including other products that do the same thing, but none of those products form mold just in a few hours of riding, they only do so if they remain in the bottle after your ride and don’t rinse it out till the next day! So rinse out your bottles immediately.

    The other thing that works 100% against mold, is to fill the bottle with about a 1/4th of the bottle with bleach, then fill the entire bottle with water, put your cap on and shake it gently in the kitchen sink so you don’t accidently get some drops on your clothing, then let the bottle sit for 24 hours, afterwards rinse the bottle out with a little drop of Dawn for dishes and hot water, then rinse again with clear hot water till all the soap is gone, and you’re bottle will no longer have mold. The Dawn thing is optional, if you don’t like the faint smell of bleach in the bottle then do the soap thing, but any trace amounts of bleach left over in the bottle after just doing a soapless rinse isn’t going to kill you, and you probably won’t even taste it even with clear water, but especially with some sort of mix in the water.

    Bleach will not damage the bottle, I’ve been doing this for many years. What will damage the bottle is throwing the bottle into the dishwasher.

  11. Chris Burkhardt says

    October 17, 2024 at 9:21 am

    I use Bivo stainless steel bottles and just put the in the dishwasher after a ride.

  12. AD Land says

    October 17, 2024 at 10:56 am

    Denture cleaning tablets. Let it soak overnight and all is well. Plus, your breath is fresher than spring.

  13. Bike Fitness Coach says

    October 17, 2024 at 11:36 am

    Diluted bleach or better yet, Hydrogen Peroxide.

  14. Z says

    October 17, 2024 at 2:04 pm

    Contact lens cleaning.tablets work and are not toxic.

  15. Jim Langley says

    October 17, 2024 at 5:25 pm

    Thanks for the excellent comments everyone!

    Jim

  16. Joe says

    October 18, 2024 at 6:48 am

    Get a good bottle brush and immediately scrub with soapy water after a ride. Do take apart and clean the bottle top. I do that once a week.

Primary Sidebar

Search

Recent Articles

  • Newsletter Issue No. 1232
  • Two New BOA Fit Systems: Dialing in Your Ride for Improved Performance, Fit, and Comfort
  • A Ticket to Ride
  • Tech Q & A: Bert’s Daughter’s E-bike Chain Drop Problem

Recent Newsletters

Newsletter Issue No. 1232

Newsletter Issue No. 1231

Newsletter Issue No. 1230

Newsletter Issue No. 1229

Newsletter Issue No. 1228

Footer

Affiliate Disclosure

Our cycling expert editors and writers choose every product we review. We may earn an affiliate commission if you buy from one of our product links, at no extra cost to you. This income supports our site.

Follow Us

  • Pinterest
  • Facebook

Privacy Policy

Still Haven’t Found What You’re Looking For?

Copyright © 2026 · Magazine Pro on Genesis Framework · WordPress · Log in

Loading Comments...