Water temperature

WildAgain Wildlife Rehabilitation, Inc.

Milk replacers for wildlife
Water temperature makes a difference

Effects of water temperature on milk replacer powder

Use of hot water is essential to mix with most powdered milk replacer containing such a relatively high fat content (≈ 40% or greater). Achieving a temperature of around 110ºF is preferable to begin the liquefaction of the various fats contained in the powder.

During the tests performed to determine the solubility of the various milk replacer powders, both hot tap water (125ºF) and water from an instant hot water dispenser (175ºF) were used. A significant issue with using either source of water is the rapid cooling effect when mixing with a dry product (at either room temperature or refrigerated) over the 30 second mixing period.

Figure 1. As shown above, the temperature of the formula after mixing for 30 seconds drops almost 30ºF on average (22%) to approximately 97ºF, which is below the target temperature of 110ºF to achieve optimal liquefaction of the various fats contained in the powder, especially certain animal fats (such as lard contained in MultiMilk® where it is the major ingredient).

Figure 2. As shown above, the temperature dropped even farther (an average 55ºF drop or 31%) when the much hotter water was used, but resulted in a formula temperature averaging 120ºF after mixing. This also serves to explain why the formula which included MultiMilk® mixed with only the hot tap water tended to have many more and larger undissolved particles when viewed under high magnification. The temperature of the formula was likely not hot enough to liquefy the animal fat in the powder (bland lard has a melting point of around 109ºF).

It is important to mention that while the milk replacer powder is mixed with hot water (about 175ºF), exceeding those temperatures could affect the nutrients.