How to Prepare Gelmix in Advance

Preparing thickened feedings ahead of time can make feeding routines easier at home, overnight, at daycare, or while traveling. Freshly expressed breast milk and prepared formula may be thickened with Gelmix up to 24 hours in advance. For powdered formula, Gelmix-thickened water may also be prepared in advance and combined with formula powder at feeding time.

Printable Guides

Download or print the step-by-step guide for the preparation method you use:

Before You Start

Wash your hands and clean the preparation surface.
Use clean bottles, containers, and feeding equipment.
Use water from a safe source when preparing formula or thickened water.
Prepare formula exactly as directed; never add extra water or powder.
Label prepared feedings or thickened water with the preparation date and time.

Always follow the Gelmix recipe for your child’s prescribed thickness, the formula manufacturer’s instructions, current CDC guidance, and your child’s healthcare provider’s feeding instructions. When storage times differ, use the shorter time.

Preparing Breast Milk in Advance

Use this method only with freshly expressed breast milk that has not been refrigerated. Prepare it while the milk is still close to body temperature whenever possible, because warmth helps activate Gelmix.

Measure the freshly expressed breast milk.
If needed, gently warm it to about 100°F/38°C.
Add Gelmix according to the recipe for the prescribed thickness.
Cap and mix well for about 30 seconds, until fully dissolved.
Refrigerate immediately after mixing in a clean, sealed container at 40°F/4°C or colder. The full Gelmix wait time still applies before serving and may occur while refrigerated; the milk will continue to thicken as it cools.
Label the container with the date and time the milk was expressed and Gelmix was added.
Use within 24 hours of adding Gelmix.

Mix again before pouring or feeding. Serve cold or gently warmed. Cold Gelmix-thickened breast milk will usually be thicker. If warming is preferred, warm only the amount needed for one feeding; gently warming it toward 100°F/38°C will usually bring it closer to the intended thickness.

Once breast milk has been warmed or brought to room temperature, use it within 2 hours. Once feeding begins, discard any remaining milk after 1 hour. Never microwave breast milk, and do not cool and warm the same milk repeatedly.

Preparing Formula in Advance

Prepared formula may be thickened with Gelmix up to 24 hours before feeding when the formula manufacturer allows advance preparation.

Prepare the formula exactly as directed by the manufacturer. For powdered formula, measure the water first, then add the exact amount of powder.
If the prepared formula is hotter than 100°F/38°C, allow it to cool toward 100°F/38°C before adding Gelmix.
Add Gelmix according to the recipe for the prescribed thickness.
Cap and mix well for about 30 seconds, until fully dissolved. For larger batches, a clean formula-mixing pitcher may be helpful.
Refrigerate immediately after mixing in a clean, sealed container at 40°F/4°C or colder. The full Gelmix wait time still applies before serving and may occur while refrigerated; the formula will continue to thicken as it cools.
Label the container with the preparation date and time.
Use within 24 hours, or sooner if required by the formula manufacturer.

Mix again before pouring or feeding. Serve cold or gently warmed. Cold Gelmix-thickened formula will usually be thicker. If warming is preferred, warm only the amount needed for one feeding. Never microwave formula.

If formula is warmed, use it promptly. Once feeding begins, discard any remaining formula after 1 hour.

Preparing a Larger Batch

If the formula manufacturer allows advance preparation, a clean formula-mixing pitcher may be used to prepare a larger batch. Refrigerate the batch immediately, label it, mix it again before pouring, and pour only the amount needed for each feeding.

Preparing Thickened Water in Advance

This method is only for powdered formula mixed with water. Gelmix-thickened water may be prepared up to 24 hours before feeding. At feeding time, add the exact amount of powdered formula required for the pre-measured water.

For individual feedings, measure the exact amount of water needed for each bottle into a clean, separate container. Always measure the plain water before adding Gelmix.
Warm the water to about 100°F/38°C.
Add Gelmix according to the recipe for the prescribed thickness.
Cap and mix well for about 30 seconds, until fully dissolved.
Keep the thickened water in a clean, sealed container at room temperature.
Label each container with the preparation date and time.
Use within 24 hours. Do not add formula powder until feeding time.

At Feeding Time

Mix the thickened water again before adding formula.
If warming is preferred, gently warm the thickened water before adding formula. Never microwave.
Add the exact amount of powdered formula required for the pre-measured water, following the formula label.
Cap and mix thoroughly. Feed promptly after the formula has been added.
Use the completed formula within 2 hours of adding the powder. Once feeding begins, discard any remaining formula after 1 hour.

Do not use room-temperature thickened water in place of required hot-water preparation. Follow current CDC, formula-manufacturer, and healthcare-provider instructions. Do not use this method with ready-to-feed or liquid concentrate formula unless specifically directed by your child’s healthcare provider.

Serving Temperature and Thickness

Gelmix-thickened breast milk or formula may be served cold or gently warmed. Cold feedings will usually be thicker. Mix again before serving; gently warming a feeding toward 100°F/38°C will usually bring it closer to the intended thickness.

If thickening for dysphagia, use the IDDSI Flow Test to verify the prescribed thickness at the temperature at which the completed feeding will be served, because temperature can affect thickness. For the thickened-water method, test only after the formula powder has been added; formula powder and serving temperature can both affect the final thickness.

Never add extra water to thin prepared formula. Changing the formula’s water-to-powder ratio changes its nutritional concentration and may produce an incorrect or unsafe consistency.

Freezing and Thawing Gelmix-Thickened Breast Milk

Gelmix may be prepared with freshly expressed breast milk that has not been refrigerated and frozen for up to 3 months.

Prepare the freshly expressed breast milk with Gelmix as directed.
Transfer it to a clean breast-milk storage container, leaving space for expansion.
Label it with the date the milk was expressed, thickened, and frozen.
Freeze immediately and use within 3 months.
Thaw the oldest milk first, overnight in the refrigerator or in a sealed container placed in lukewarm water.
Never microwave or refreeze completely thawed breast milk.
After it has completely thawed in the refrigerator, use it within 24 hours. Once warmed or brought to room temperature, use it within 2 hours.
Mix well. If thickening for dysphagia, repeat the IDDSI Flow Test at the serving temperature.

Important Powdered Formula Safety Information

Powdered formula is not sterile. Infants younger than 2 months, born prematurely, or with a weakened immune system may require additional preparation precautions, including very hot water. Follow current CDC guidance and your child’s healthcare provider’s instructions.

Do not use room-temperature Gelmix-thickened water in place of required hot-water preparation. Do not use the thickened-water method if the formula manufacturer or your child’s healthcare provider requires formula powder to be mixed with water at a different temperature.

Frequently Asked Questions

Does Gelmix change the formula recipe?

No. Always prepare formula exactly as directed by the manufacturer. Do not add extra water or powder. Measure the plain water before adding Gelmix.

Does a prepared feeding need to be warmed?

No. It may be served cold or gently warmed. Keep in mind that it will usually be thicker when served cold.

Why is a refrigerated feeding thicker?

Gelmix continues to thicken as the feeding cools. Gently warming it toward 100°F/38°C will usually bring it closer to the intended thickness. If thickening for dysphagia, verify the prescribed thickness at the serving temperature with the IDDSI Flow Test.

Can I use previously refrigerated breast milk for advance preparation?

No. This method is intended for freshly expressed breast milk that has not been refrigerated. This avoids warming previously refrigerated milk to activate Gelmix and then cooling and refrigerating it again.

Can I prepare a larger batch of formula?

Yes, if the formula manufacturer allows advance preparation. Use a clean formula-mixing pitcher, refrigerate the batch immediately, label it, and pour only the amount needed for each feeding.

Can I use the thickened-water method with any formula?

No. This method is intended for powdered formula mixed with water. Follow the formula manufacturer’s instructions. Do not use it with ready-to-feed or liquid concentrate formula unless specifically directed by your child’s healthcare provider.

Should I perform the IDDSI Flow Test on thickened water?

No. If thickening for dysphagia, test the completed formula after the powder has been added and at the temperature at which it will be served.

What should I do with leftovers?

Discard any breast milk or formula remaining in the bottle 1 hour after feeding begins. Do not refrigerate or reuse it. Discard unused thickened water 24 hours after it was prepared.

Gelmix Recipes

Visit the Gelmix recipe library for preparation instructions and recipes for different thickness levels.

References

CDC: Infant Formula Preparation and Storage

CDC: Breast Milk Storage and Preparation

FDA: Prepare and Store Powdered Infant Formula Safely

NASPGHAN: Pediatric Gastroesophageal Reflux Guideline Summary

This information is for general education and does not replace current CDC guidance, the formula manufacturer’s instructions, or instructions from your child’s healthcare professional. Follow the most cautious applicable preparation instructions; when storage times differ, use the shorter time.