Frequently Asked Questions

The Ceres Chill system is so simple, it can seem complicated.

Our innovative Chiller uses a minimum number of parts to accomplish everything! Rather than browsing through the questions below, you may simply want to check out our User Guide to better understand all the ways you can use it and how easy it is to clean.

Does the Chiller work with all major breast pumps?

Yes! Ceres Chill Breastmilk Chiller is compatible with most major narrow neck pumps without an adapter: Medela (except Freestyle Flex*), Evenflo, Ameda, Ardo, Gland, Kidstime, Nibble, Babysteps, Bellema.

If you purchased your Chiller before September 2023, you likely have a previous version of our upper components. Medela’s new Freestyle Flex and similar new Medela pump styles do not work with the previous version of the upper cup and connector. If you are having this issue, please reach out to us — we recently designed new upper parts to accommodate this change and can work with you on a replacement set. 

*If you purchased your Chiller after September 2023, your Chiller will have new parts.

If you have a cordless or hands-free pump, there is no need for an adapter!

The Chiller also pairs SO well with wearable pumps such as a Willow, Elvie, Momcozy, Freeme, and more! All you need to do is pour your milk directly from the pump into the chiller.

With the Ceres Chill Universal Pump Converter, the Chiller works with Spectra, Phillips Avent, Bella Baby, Baby Buddha, Cimilre, and Motif by Aeroflow. We have heard of some moms having success with these adapters as well.

If you have a Lansinoh pump, please choose the Lansinoh converters to allow your parts to connect to the Chiller!

If you don't see your pump listed here, please reach out to us so that we can confirm whether you need an adapter and to make sure we get you what you need!

How does pumping warm milk into a thermos cool it and keep it cold? 

The Ceres Chill Breastmilk Chiller is designed to chill and store freshly expressed breastmilk and bring it down to refrigerator temperatures, then maintain it at safe temperatures for hours. According to the Academy of Breastfeeding Medicine, breastmilk can be kept at 59*F for up to 24 hours.

With its amazingly engineered, patented, dual chamber system, you just need to add a handful of ice cubes and a bit of water to the Chiller’s chamber to get 16-20 hours of storage. Just pump directly into the Chiller or add your milk into it throughout the day. As the ice melts, it transfers its cooling power to your milk!

And we can't say it enough, if you love hard evidence of awesomeness like science, charts and consumer safety reports, we have all of that for you here.

Once the ice melts, is my breastmilk still safe?

It's likely perfectly safe! The ice does need to transfer its chill to your milk to bring the temperature down, so it will melt after several hours. The high quality seal and cold water still work to keep everything super cold for the rest of the time!

Always make sure that you have enough ice in your Chiller chamber -there should be about 6–8 cubes (or more — as many as you can fit) and a tiny splash of water to help everything settle in. Adding too much water can cause the ice to melt quicker than it should!

Here’s an article with really great information on what is happening with your Chiller: On no, my ice is melting fast!

As stated in the article linked above, milk can be safely stored at 59ºF for up to 24 hours. Whether your milk is placed in a fridge, cooler, or Chiller, it takes time to bring the milk from body temperature (around 98.6ºF) down to 59ºF!

This video below also has some fantastic information on everything you need to know about using and loving your Chiller: All you need to know when using your chiller!

Does the Chiller need to be sterilized?

The FDA indicates that while it’s not possible to fully sterilize pump parts at home, dishwashing soap and warm water will do just fine:

“All breast pump parts that come in contact with breastmilk, such as bottles, valves and breast shields, should be cleaned after each use. It is not possible to completely sterilize breast pump parts at home, even if you boil them. However, sterilization is not necessary to keep these parts safe and sanitary. You can do that by thoroughly washing away germs and bacteria with liquid dishwashing soap and warm water.”

All Ceres Chill parts do fit in home sterilizers, but the high heat and intensity can be hard on the parts and affect the finish on the outer chamber. We recommend hand washing the outer chamber and tossing the inner chamber and plastic parts in the top rack of the dishwasher!

As an extra cleaning measure, you can place the inner chamber in boiling water and pour boiling water inside the outer chamber, but as with all breastfeeding gear, prolonged exposure to high heat can damage the parts. We do not recommend actively boiling the parts for sustained periods. It's best to avoid boiling the plastic parts or the outside of the outer chamber.

Check out this blog post for more the important sterilizing and disinfecting information!

*Parents should not use any products (like certain soaps or cleaning tablets) unless the products indicate that they are safe for infants and use of food grade stainless steel, BPA free plastics and platinum silicone.

Does the Chiller come with a pump or pump parts?

Our Breastmilk Chillers do not come with a pump or pump parts, but they are compatible with all major pumps/adapters (see FAQ #1). This allows you to choose the pump that is best for you and still be able to pump directly into the Chiller, knowing that your milk is safely stored without the added risk of contamination that other storage systems have due to multiple containers and chilling mechanisms. 

Can I use a hands-free bra and double pump?

Yes! A fully assembled Ceres Chill Breastmilk Chiller has all you need to double pump with a hands-free bra. With each Chiller, you get one lightweight 12-ounce Milk Chamber (it weighs less than an 8 oz capacity plastic bottle) that connects directly to your pump and another up-to-8 ounce capacity chamber which doubles as the cup so you can easily pump both sides without bringing a ton of extra plastic in a cooler with you everywhere you go.

Can I add warm milk to already chilled milk?

Recent research says yes! Knowledge is power so we want to give you all the knowledge we have. We are so excited to share the recent science and studies about the power of breastmilk and the benefits of pooling milk over the course of 24 hours on our page dedicated to this important area of research. 

We know where you're coming from with this question. There is a lot of conflicting and outdated information on the internet on this topic (and all parenting topics, really). Moms need to do what they feel is best for themselves and their babies, whether it is using a cooler with separate bottles, combining their milk in one Chiller, or using one Chiller to chill and the other to store milk as needed. 

Why use a Ceres Chill Breastmilk Chiller instead of a cooler or a fridge?

No more worry and so much more freedom! Pumps are improving every day so why should breastmilk storage be stuck in the stone age? Ceres Chill provides you with a safe, long-term solution that you can easily keep on your nightstand, at your desk, in the diaper bag, or tucked in your carry-on luggage. Nothing else in the world allows moms to so easily and safely store up to 27 ounces of breastmilk or formula for over 20 hours. However, we understand that conditions may vary. For this reason, we recommend adding ice to the inner chamber between 12 and 20 hours of chilling based on the amount of milk being added, ambient temperatures, and other challenging surrounding conditions.

Coolers only last for 6–8 hours (eek — can't forget the milk at work, in the car or in your bag!). Coolers require advanced freezing (don't ever forget to freeze the freeze pack overnight!). They are also jammed full of lots of plastic (ick and ugh) and typically hold only 20 ounces. And there are just so many parts to hand-wash and sanitize! How can we possibly do everything we need to do in so little time and with so much baggage?!


One Chiller to chill your milk and one to warm it makes for a happy baby — road trips, long walks and life just became waaay easier! One Chiller filled with hot water can warm up to three bottles over 8 hours. Need more warm bottles? Just add hot water to the outer chamber and go!


The Chiller allows you to safely chill and store up to 27 ounces of breastmilk by your bedside for midnight pumps, at your desk, in your car, or in your luggage for 20+ hours. Traveling is such a breeze without ice packs or hassles with airport security. Less plastic is such a relief!

For moms facing the incredible challenges of caring for a NICU baby or working super-long shifts, their only option is no longer an inconvenient fridge. Our Chiller provides 20+ hours of safe storage for up to 27 ounces of milk or formula.


This super high-quality bottle has been specifically and rigorously tested to ensure it is safe for infants and can keep your breastmilk safe without the need to purchase more plastic and disposable storage. Moms know it is truly hard to calculate the value of all of the breastmilk that gets dumped when coolers fail, we forget to freeze the chemical ice packs, or we have to take long work trips with complications involving TSA and coolers.It might surprise you that Ceres Chill's price is competitive with the many traditional options out there...but the Chiller is even better because it’s sustainable and higher quality. Coolers range in cost from $18-$250; a Medela Storage system of plastic baggies and bottles is about $34 so with the coolers you are up to $52; Mini fridges for offices or bedsides are typically $90 - $250. Ceres Chill replaces all of the hassle and costs for much less in the long run. The Ceres Chill gives a piece of mind that is truly priceless!


Finally, a baby product that is also for moms and dads! These chillers are not disposable like all the coolers and plastic that ends up in the trash. Ceres Chill parents LOVE their chillers and use them long after breastfeeding days are a distant memory. These happy uses are endless: Hot coffee all day. Cold water at the gym or on a long hike. And absolutely anything can be chilled without dilution, so you can do something fun like chill an entire bottle of chardonnay in 20 minutes or sip the perfect iced coffee at the park. One Ceres Chill Army dad uses it to keep his hollandaise sauce warm while he puts the finishing touches on brunch. Ceres Chill is the best water bottle and thermos you have ever treated yourself to!

How is a Ceres Chill Breastmilk Chiller different from a regular thermos?

Here are three BIG differences:

1. Thermoses can't keep freshly expressed breastmilk at a safe temperature. A regular thermos can keep milk cold, or keep coffee hot, but the Ceres Chill safely and reliably changes the temperature so you can pump directly into the Chiller and bring the temperature down to a safe level.

2. Ceres Chill is tested and certified for use with infants. If you love hard evidence of awesomeness like science, charts and consumer safety reports, we have all of that for you here.

3. Because it was designed by a pumping, hardworking mom for other pumping, amazing, hardworking moms, it is versatile and reliable. This means it has all the compatible threading to connect your pump directly to the Chiller so you can pump into it and eliminate added risks of spills or contamination. You get convenience and peace of mind knowing you are not needlessly risking your baby's milk or formula. 

How do I know what size Chiller is right for me? What is the difference in capacity of the Demigoddess Mini Chiller and the Chiller?

The Chiller dimensions are similar to that of a standard thermos (11 inches x 4 inches), so it fits perfectly in most medium-sized bags. It’s easy to carry and definitely more space-saving than a full cooler! The inner chamber by itself is about the same weight and circumference as a 5-ounce Medela bottle, with a height of 7 inches and a diameter of 2 inches.

At 8 inches by 4 inches, the Demigoddess dimensions are similar to that of a narrow-base travel mug and will fit in even your narrowest cup holder. It is designed for 16+ hours of chilling for up to 12 ounces of breastmilk. 

How long can I store my milk in the Chiller?

The Ceres Chill Breastmilk Chillers can safely store your milk for 16-20 hours. The Academy of Breastfeeding Medicine states that breastmilk can be kept at 59ºF for up to 24 hours, and the Chiller works to keep your milk at that temperature or less for 20 hours. After that point, it's important to transfer your milk to an uninsulated container in the fridge to make sure that you're following the milk storage guidelines for what temperature you should keep your milk.

Can I keep my milk in the Chiller for longer than 20 hours?

We don't recommend keeping your milk in the Chiller past the 20-hour mark unless it's an emergency and you don't have access to a fridge. If you absolutely need to use the Chiller for longer, be sure to refill the ice frequently and monitor the temperature of your milk.

Does Ceres Chill offer discounts?

Yes! If you're a healthcare worker, essential worker, first responder, or military service member/spouse, get your Essential Worker Discount at checkout with GovX or register here to receive a well-deserved discount. We love honoring our hardworking hero families with 20% off all their orders, always.

If you don't qualify for our Essential Worker Discount, don't worry! We offer lots of other chances to save at different times throughout the year. Sign up for the “Ceres Club” at the bottom of this page and follow us on Instagram, TikTok or Facebook to get updates on exclusive discounts. We're always thinking about you, coming up with amazing deals and awesome free gifts so we can better help you get through your breastfeeding journey with less stress and more style.

Do I need more than one Chiller? How do I store 12–27 ounces?

Our 27-ounce Ceres Chill Breastmilk Chiller is designed so that you only need one to carry all the breastmilk that most moms likely produce in a 20-hour period. 

Using the inner chamber for storing up to 12 ounces is super easy and just requires a handful of ice cubes in the outer chamber while you pump directly into the inner chamber (and upper cup if you are double pumping). 

We understand some moms might think the size of our original Chiller is too big, and that is why we created the Demigoddess Mini Chiller! It is the size of most travel coffee mugs, and super compact and portable. The Demigoddess is designed to hold up to 12 ounces of milk with a more compact size.

To expand your storage capacity with each of your Chillers, you will use the inner chamber for your ice (instead of putting ice in the bigger, outer chamber). Using this method, you can store up to 27 ounces! You just need to remember to keep your hands clean if you touch the inner chamber and always set your inner chamber on a clean surface (the inside of your upturned cup is perfect for this). You can pump directly into the outer chamber by reattaching the connector. Moms using the double capacity method should add ice to the inner chamber after 10 hours to ensure safe chilling over very long or very hot days.

All of the parts working together can be a little confusing but a quick look at our User Guide shows you all the easy storage methods. 


But sometimes you could really use the convenience of two chillers. For some moms, they want one Chiller to chill the milk and the other to store it. And it is always nice to have one to grab if the other is in the dishwasher! Not to mention — your Chiller is also a bottle warmer — mind blowing, we know!

That’s why we have created the Warmer/Chiller Duo - to give you two great Chillers for much less money! As a mama, you're juggling everything at once and may not even have time to wash your Chiller. Having two Chillers gives you even more flexibility! 

Can I freeze the inner chamber? 

We don’t recommend freezing the inner chamber. The inner chambers are designed to be as lightweight as possible for pumping and transport purposes, so the stainless steel is a bit thinner on that part. Some freezers are super epic and can cause the bottom to pop out due to expansion, or in rare situations even crack!

Some moms do still choose to freeze their inner chambers for convenience - if you choose to do so, be sure to only fill it about 8 ounces full and leave it completely uncapped. Unfortunately, there is still a risk of damage.

What's the best way to store my milk if I am trying to build up a stash?

Check out The Ceres Chill Milkstache and The Ceres Chill Milkstache Luxe — a really beautiful, versatile solution without the mess, expense, trash and headache of a million plastic baggies. They are a really great answer for moms that are struggling to ensure their milk is safely stored for months without buying a second freezer and going through mountains of disposable, overpriced plastic baggies.

Why is there condensation on the inside of my chiller?

Oh! That’s completely normal. That water is actually coming from your milk as it comes in contact with the cold inner ice chamber. Breastmilk is over 85% water, so it will just be mixing back into where it came from!

If you notice condensation before adding any milk, that means that there's humid air in your outer chamber. You can help prevent this by making sure that your parts are fully dried and stored in a cool place (like the fridge) before use. We have a really cool blog about this that might help!

Condensation on your inner chamber? Here's why! – Ceres Chill

Can I put my entire Chiller in the fridge?

We do not recommend putting the outer chamber of your Chiller in the fridge! Please note that the outer chamber is an insulated container, which means that it will prevent external refrigeration. Without ice in the inner chamber, the outer chamber will essentially act like a thermos and keep cold liquids cold and hot liquids hot. For this reason, we do not recommend putting fresh milk in the outer chamber and putting it in the fridge. The Chiller will not be able to effectively chill and store your milk that way.

However, you can absolutely store your stainless steel inner chamber in the fridge! It is really great for transporting breastmilk to and from daycare or work without worrying about plastic bags leaking.

To get safe storage, be sure to use any of the methods outlined in our User Guide. With just a few ice cubes and a tiny splash of water, the Chiller safely stores your milk on its own. It does not need to be placed in the fridge or freezer.

How does the Chiller do all the things you say it does?

We get it, it can be hard to figure out the first time. The Ceres Chill Breastmilk Chiller has a small number of parts that recombine to meet all your needs throughout the day — commuting, working, traveling, and having fun out in the world with or without the baby. Any caregiver can take the Chiller on an adventure!

Hear Chiller mom Terra explain how it works.

Can I use the Chiller as a bottle warmer?

Yes! Your Ceres Chill Breastmilk Chiller is incredibly versatile and can be used to warm baby bottles on the go. Just put hot tap water in the outer chamber and seal it up as usual. Then when you are out and want to warm milk or formula, just pour the cold milk/formula into the empty inner chamber by unscrewing the cup and small cap. Close it all up. Wait 7-10 minutes and then pour the warmed contents into your favorite baby bottles. The Chiller can warm up to 3 bottles over the course of 10 hours.

Can I use the Chiller with formula?

Yes! Absolutely! Your Chiller is an excellent way to safely transport chilled formula or warm a bottle of formula for your baby while you're on-the-go.

Check out our blog for all you need to know about using the Chiller for formula!

How many ounces does a Ceres Chill Breastmilk Chiller hold?

The OG Chiller stores 12–34 ounces for up to 20 hours, and the Demigoddess Mini Chiller can store 6-12 ounces of milk or formula for up to 16 hours!

What are Ceres Chill products made of?

Our products are made out of the highest quality materials, because moms deserve the best!

Breastmilk Chiller - The inner chamber and outer chamber are made out of 304 Food Grade stainless steel that has been independently tested by Eurofins (a United States laboratory approved by the US Government/Consumer Protection Agency) to ensure that it complies with all Consumer Protection standards and FDA/EU/Prop 65 requirements for the safest, food safe infant products. The upper cup, cap and connector are made out of BPA-free plastic.

Milkstache - The Luxe Milkstache chest is made with 304 Food Grade stainless steel and the Plum Milkstache chest and the sides of the trays are made out of BPA-free plastic. The bottom of the trays and the flexible tops are made out of laboratory-tested food grade silicone.

Shield Maidens - Our nipple shields are made out of laboratory-tested, food grade silicone.

Check out our science page for all of the cool consumer tests reports and information!

Can I use my FSA or HSA card to purchase Ceres Chill Products?

Yes! We are authorized to accept FSA and HSA cards directly on our website. Ceres Chill is FSA and HSA approved because we fall under the breast pump and lactation supplies category as a medically necessary product! The Chiller, Milkstache and Shield Maidens are all examples of eligible expenses for these special medical funds.

**Please know that while we are authorized to accept these cards, the decision to approve or deny a transaction is up to the card issuers. They can still decline your purchase, even if you're buying an eligible product. Based on our experience, FSA cards tend to be a bit trickier to approve.

If your card gets declined, please reach out to us at We may not be able to push that payment method through, but we can provide you with an itemized receipt that you can use to request a reimbursement.

Want to learn more about FSA and HSA? Check out our blog here!

How about airport security screening?

We have taken all TSA and government office protocols into consideration with this design. Using an open water chamber and a separate breastmilk reservoir that can be easily and cleanly tested without compromising your milk, Ceres Chill moms will skate through security as smoothly as any of us ever did...which is not to say that TSA is easy, just that Ceres Chill and your breastmilk won't make it harder than it needs to be.

For more information on traveling with your Chiller, check out our blog post here!

I'm having trouble using the Chiller. Is it working as expected?

We definitely want to make sure that everything is working as it should! Check out our troubleshooting page and reach out to us at with any questions. We always want to help.

What about returns and refunds?

If you don’t love your Chiller and it doesn’t make your life easier, return it anytime within a year for a refund of the purchase price. Check out all of our return information here!