How to Clean and Store HydraPak Soft Flasks So They Last for Years
By HydraPak | Performance Hydration Reservoirs, Soft Flasks ... | Published: 2026-10-13
Category: Tips & Care
A practical, step-by-step routine for cleaning, drying and storing HydraPak soft flasks so they stay mold-free, taste-neutral and ready for years of long runs.
Quick answer
Rinse your HydraPak soft flask with warm water and a drop of mild dish soap immediately after every run, scrub the inside with a soft bottle brush, then air-dry it fully upside down with the cap off before storing it loosely capped in a cool, dark cupboard. Skip the dishwasher and never store a damp flask sealed, because trapped moisture is what shortens a soft flask's life.
Why soft flask care is different from hard bottle care
Soft flasks are made from flexible, compressible TPU film, and that flexibility is exactly why they need gentler handling than a rigid bottle. Sharp brushes, hot dishwasher cycles and prolonged direct sun can stress the welded seams and the film itself. The good news: because the material is soft, you can turn most flasks inside out or reach every corner with a soft brush, so cleaning is actually easier than it sounds.
The real risk is not dirt, it is moisture. A flask that looks dry on the outside can still hold a film of water in the folds, and that is where mold and a stale taste start. Treat drying as the most important step, not an afterthought.
What you need before you start
You do not need a special kit. Warm water, mild dish soap, a soft bottle brush or a dedicated flask brush, and a drying rack or a clean dish towel are enough. A small funnel helps if you want to dry the inside faster with a paper towel twist.
Avoid bleach, harsh sanitizers and abrasive sponges. If you use a sanitizing tablet or solution, follow its instructions and rinse thoroughly afterward, because residue can leave a taste in the next drink.
How often to clean and when to deep clean
For plain water, a quick rinse and air-dry after every use is usually enough, with a soap wash every few uses. For sports drink, electrolyte mix or gel residue, wash with soap after every single use, because sugar and salt feed mold quickly.
Deep clean weekly during heavy training, and always before storing a flask for more than a few days. If you notice a lingering smell or a slimy feel that rinsing does not remove, that is your signal to deep clean immediately rather than wait for the weekend.
The 6-step clean-and-store routine
- Empty and rinse right away: As soon as you finish, empty any leftover drink and rinse the flask inside and out with warm water. Do not let sports drink sit in the flask overnight. Checkpoint: if you can still smell the drink after rinsing, go straight to a soap wash.
- Wash with mild soap and a soft brush: Add a drop of mild dish soap and warm water, then gently scrub the inside with a soft bottle brush. Work the brush around the base and shoulders where film folds over. Common mistake: using a stiff brush or scouring pad, which can abrade the soft film.
- Clean the cap and valve separately: Disassemble the cap, bite valve or gel cap and rinse each piece under warm running water. For gel caps, flex the valve gently to flush out sticky residue. Checkpoint: hold the valve up to the light, and if you see residue, soak it a few minutes and rinse again.
- Rinse until no suds or taste remain: Rinse thoroughly with warm water, then fill and empty once more with clean water. Soap residue is the most common cause of a strange taste in the next drink. Common mistake: stopping at the first clear rinse instead of a second fill-and-empty cycle.
- Air-dry fully, upside down and open: Shake out excess water, then hang or stand the flask upside down with the cap off and the opening spread so air can move through. Dry caps separately, not snapped onto the flask. Checkpoint: no visible droplets and no cool, damp feel inside before you move to storage.
- Store loosely capped in a cool, dark place: Once bone dry, store the flask loosely capped or fully open in a cupboard away from direct sun and heat. Keep it unassembled from its cap if space allows. Common mistake: sealing a slightly damp flask in a gym bag, which is the fastest route to mold and a shortened lifespan.
Flask-specific care notes
- SkyFlask™ Speed IT 500ml: The SkyFlask Speed IT 500ml is a minimalist handheld with a thumb loop and an adjustable, sweatproof strap, and it keeps hydration cool 38% longer than a standard flask. Because the strap and loop sit against your hand, they pick up sweat and salt. Wipe the strap and loop with a damp cloth during your cleaning routine so the fabric does not stiffen or smell over time.
- FuelFlask™ 250ml 2-Pack: The FuelFlask 250ml 2-Pack ships with two flasks and four caps total, one gel cap and one liquid cap per flask, so you can mix and match caps. Gel caps trap sticky residue in the nozzle. Rinse each cap separately under warm water and let both caps and both flasks dry fully apart, or gel sugar will harden inside the valve.
- Ultramarathon Bundle: The Ultramarathon Bundle pairs a SoftFlask Speed 500ml for vest carry, a SkyFlask Speed 500ml for handheld use, and a FuelFlask 250ml 2-Pack with interchangeable gel and flip caps. A bundle means several flasks and caps in rotation. Wash and dry them one at a time and store them unassembled, so you never mix a damp cap onto a dry flask.
