SmartStash Tracking Bags: How to Log and Rotate Your Milk Supply
By Willow: Wearable Breast Pump – Willow Pump | Published: 2026-11-02
Category: How-to Guides
Learn how SmartStash milk tracking bags work with the Willow app, plus a step-by-step routine to log, rotate, and thaw your freezer stash without guesswork.
Quick answer
Use SmartStash tracking bags as your single source of truth: scan each bag into the Willow app when you store it, then check the app before every pump and feed so you always thaw the oldest milk first.
Why a scan-based log beats a mental note
A freezer stash grows in small increments, and those increments are easy to forget. Writing dates on bags helps, but a written log still depends on you remembering to check it. SmartStash bags add a scannable code that pulls the bag’s information into your digital stash in the Willow app, so the inventory updates as you store. That matters most in the first weeks of building a stash, when bags pile up faster than you expect.
Where the routine can break down
The two weak points are the moment you seal a bag and the moment you thaw one. If you skip the scan at storage, the app will undercount your stash. If you grab a bag without checking the app, you may thaw newer milk while older milk sits in the back. Build both checks into your routine rather than relying on memory. The steps below cover the full loop, from filling to feeding.
Your step-by-step SmartStash routine
- Label and fill the bag before you seal it: Write the pump date on the bag, then add milk up to a level you can read clearly. Seal according to the bag’s instructions and lay it flat to freeze if you want stacked storage. Checkpoint: the date is legible before the bag goes into the freezer.
- Scan the bag into the Willow app right away: Open the Willow app and scan the bag’s code while the bag is still in your hand. Confirm the entry appears in your digital stash before you put the bag away. Mistake to avoid: scanning a stack of bags later, when you no longer remember which date belongs to which bag.
- Store newest bags at the back: Place freshly scanned bags behind older ones so the oldest milk sits at the front. If your freezer space allows, keep a single row or bin for “next to use.” Checkpoint: the front of the bin is always the oldest milk you have.
- Check the app before every pump session: Glance at your digital stash to see what is already stored and how old it is. This prevents duplicate bags from being buried and helps you plan how much fresh milk to freeze. Mistake to avoid: pumping and freezing without checking, which can push older bags out of rotation.
- Thaw the oldest bag first, in the refrigerator: Move the oldest bag from the freezer to the refrigerator to thaw. Keep it labeled and use it within the timeframe your storage guidance allows. Do not refreeze thawed milk. Checkpoint: the bag you thaw matches the oldest date shown in the app.
- Update the app when the bag is used: Remove or mark the bag as used in your digital stash as soon as you pour it. This keeps your inventory accurate for the next check. Mistake to avoid: letting used bags stay in the app, which makes your stash look larger than it is.
Product facts
- Breast Milk Storage Bags with SmartStash™ Tracking: These durable, leak-proof bags have a scannable, AI-enabled code that auto-inputs bag information into your digital stash in the Willow app. You can log a bag in seconds instead of keeping a separate paper list, which makes daily tracking more likely to stick.
Breast Milk Storage Bags with SmartStash™ Tracking
