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Hands-on Gear Review
Kiinde Kozii ReviewPrice: $70.00 List | $49.99 at Amazon - 29% off
Pros: Slow warming water bath technology, user-friendly, versatile, timer in minutes
Cons: Expensive, no end of cycle beep, multiple cleaning steps
Bottom line: Consistent, simple, innovative, and works with any bottle
Temperature or Timer-Based: Timer
Auto Shut-Off: Yes; Water Retracts into Reservoir at Shut-Off
The Kiinde Kozii earned Editors' Choice with an overall score of 81 of 100. It excels in health and safety, ease of use, and warming efficiency via patent-pending SAFEHeat technology. This uses an inventive circulating water bath that controls water temperature via a thermostat and at the end of cycle, water retracts into its reservoir.
For more information regarding safe handling of expressed breast milk, please see our article titled Best Practices for Handling Breast Milk.
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Our Analysis and Hands-on Test Results
Kiinde Squeeze baby bottle whose Kiinde Twist Pouch hooks up to any breast pump via a variety of adapters for direct pump-to-pouch expression. A uniquely designed Kiinde Keeper then accentuates the system with a modern freezer storage solution that is designed to avoid bag puncture.
Kiinde's water bath technology is termed SAFEHeat and that's exactly what it does, that is, safely heats breast milk or formula (frozen or refrigerated) at a low temperature, nutrient-preserving water bath. The company states that this is the first warmer designed specifically to follow all guidelines set forth by the Center for Disease Control and the United States Department of Agriculture to safely thaw and warm breast milk.
Health and Safety
Born Free Tru-Temp and the Cuisinart BW-10 for easily accessible, quick viewing.
An innovative feature of the Kozii is at turn on, an internal convection pump sends water up and out of the reservoir to flow around the container. There is an overflow valve at the top where water flows back into the reservoir should the unit be filled higher than the "Full" indicator. At auto shut-off, water drains back into its reservoir. This means that, heat is mostly removed from the bottle as soon as it shuts off and users are less likely to come into contact with warm water. However, like other warmers, if set to too high a heating setting, the Kozi can be made to overheat milk.
As the Kozii doesn't have a end of cycle beep, we recommend setting a separate timer to alert when a bottle is ready. The timer does run a low "ticking" noise for 30 seconds at the end of cycle, but it isn't loud enough. Even though water retracts back into the reservoir, if a bottle sits inside the chamber, milk temperature will continue to rise until removal.
In our testing, the Kiinde had the very best performance of any tested warmer when used at the manufacturer's recommended settings. It shut off as it reached 80F and then continued to warm gradually to reach no higher than body temperature. However, in our maximum heating test, where we ignored the manufacturer's recommendations and simply turned it to maximum and left it running, we did find that the Kiinde would overheat and after 12 minutes reached 122F. It is worth noting that 3 of the 7 competing warmers never overheated in our tests, even when run at their maximum heating setting. Thus, we'd advise following Kiinde's instructions for the Kozii, since even this sophisticated device can overheat if misused.
Ease of Use
Its water chamber fits standard and wide-mouth bottles such as the Top Pick Comotomo and Best Value Tommee Tippee Feeding as well as any material including plastic, glass, silicone, and stainless that may be found in such items as breast milk storage bags, liner bottles, and baby food jars.
The reservoir is easy to fill with a 2 cup capacity. Refilling only need occur about every 5 to 10 uses. The minute timer is intuitive and lets you know how much time is left before baby's meal is ready. For use, fill the warming chamber with water to just above the word "Full"; there should always be water between "Empty" and "Full." That's all it takes before you're ready to warm.
During the warming cycle, the chamber fills with warm, circulating water via an internal convection pump, gently heating the bottle. At baseline, the Kozii emits a consistent hum and tick-ticking. At the end of the cycle, just before it automatically shuts off, water retracts back down into the reservoir. If you need to heat another bottle, you can start the unit up right away, just be sure to reduce the time by 30 seconds.
We do wish this warmer had an audible end of cycle beep to let you know when the time is up. We feel the ticking just isn't loud enough and when it turns off about 30 seconds after the cycle is complete, it can be easily tuned out and missed.
The Kozii earned an 8 of 10 in warming efficiency. Depending on the bottle material, quantity and starting temperature of milk, it could take anywhere between 4 to over 12 minutes to warm milk via its gentle circulating warm water bath. It will take a short initial trial period to find the right setting for your particular needs. So, be patient. The extra time is well worth it to preserve breast milk nutrients.
However, once that sweet spot is found, the Kozii executes warming consistently. In our testing, at recommended settings, it took 4 ounces of refrigerated milk in a small Lifefactory Glass Bottle with silicone sleeve 5:50 to reach 80F and at maximum setting, 6:00 to reach the same temperature.
For best consistency, efficiency, and quiet with the Kozii, make sure that water is constantly flowing through the overflow drain during warming. If you have a small bottle or a bag of breastmilk (typically lighter than a bottle), then you may need to add water above the "Fill" indicator; there is a secondary line inside the chamber for this use.
Always make sure the Kozii has sufficient water prior to running. In the event that the Kozii is run dry, its safety thermostat may trip which will mean that its water bath will not be heated. In this event, you need to re-set the system following the troubleshooting instructions. However, do not make this a habit as the entire system will stop working permanently if it is tripped more than 3 times.
Ease of Cleaning
The Kozii scored a 4 of 10 in ease of cleaning which is a straightforward but involved process. With a hidden reservoir, it is important to follow cleaning instructions to avoid mold growth as well as hard mineral build-up internally.
Great for home use, daycare, or travel, the Kozii is versatile with even the widest of bottle systems. It is compact and easy to use, but make sure you have patience for regular maintenance. With a circulating water bath, it is perfect for those who are warming expressed breastmilk. And, without a wait time between uses, it is a also great warmer to use with multiples.
In our opinion, Kozii's innovative technology is worth its price tag of $70. If you're looking for a more budget-friendly option, however, the slower but very functional Chicco NaturalFit Two-in-One is the way to go.
Kiinde's design of Editors' Choice Kozii is unique with SAFEheat technology and a hidden water reservoir with internal convection pump. Excelling in health and safety, ease of use, and warming efficiency, a bit of extra time spent warming is well-worth the wait. We highly recommend this warmer. It certainly stands out in the crowd of available warmers.
— Ruth and Ben Traxler & Juliet Spurrier, MD
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