food science

Destination Sublimation (The Basics of Freeze-Drying)

As a kid growing up in the 60s, I have fond memories surrounding the USA’s first lunar landing, especially all the crazy-fun space drinks and snacks that came along with it, like Tang, Pillsbury Food Sticks and astronaut ice-cream. Although Tang and the food sticks were kinda gross, the astronaut-ice cream was the stuff of magic. It was light as a feather, crispy and didn’t melt at room temperature. Best of all, it looked just like a regular old slice of ice cream. Behold the brainy beauty of freeze-drying.

When OuttaMyKitchen! dog treats were initially developed, they were dehydrated, not baked. While both are perfectly reasonable cooking methods, the shelf-life of the finished product is limited. And, for customers and retailers alike, the shelf-life of real food, like OMK’s yummy dog treats, is a valid and important concern. After conducting some research into methods of food preservation, freeze-drying was clearly the optimal means of retaining freshness of foods without altering their appearance or nutritive value.

What makes freeze-drying so special? How is it different from dehydrating? While dehydrating use circulating heat to remove moisture by evaporation, which changes it from liquid to a gas, freeze-drying employs sublimation, whereby ice (water’s solid form) is directly transformed to its water vapor (water’s gaseous form). This transformation is a function of atmospheric pressure. At sea level, ice will melt into water before evaporating. When pressure becomes sub-atmospheric (like inside a vacuum), that same ice will sublimate directly into water vapor as it heats, bypassing the liquid phase entirely, removing water nearly completely. In freeze-drying, this is achieved by creating a vacuum, which lowers the atmospheric pressure by sucking out air. So, in short, a freeze-dryer consists of freezing and heating elements and a vacuum pump. It’s a time consuming process that cannot be rushed; each batch of treats requires 24-27 hours to dry.

Freeze-dried foods are light and crispy and look exactly the same as they did before being processed. It’s sort of Willy Wonka-esque. A strawberry looks (and tastes) exactly like a strawberry, only it’s dry, crunchy and much lighter in weight. OuttaMyKitchen’s freeze-dried treats have a pleasing tendercrisp texture, much like that of shortbread. They can be easily snapped into smaller pieces for training or for smaller dogs. Same great flavor, new texture and extended shelf-life…what’s not to love? Oh, I almost forgot to mention, they’re now grain-free!

SteveBaxter, commandeering the freeze-dryer cart.

SteveBaxter, commandeering the freeze-dryer cart.

Keep Calm and Science On

Everybody knows that my mommie is a very good cook. In fact, her favorite books are cookbooks! And a big part of what she loves about cooking is the science behind it, the processes through which food is transformed into an unforgettable sensory experience. So, it makes sense that the yummy dog treats she makes for me are rooted in food science.

When Mommie started making me dog treats, she had to figure out a way to do it so that she could work at her day job without having to be in the kitchen 24/7. She accomplished that with 2 handy pieces of equipment: her water immersion circulator (sous vide) and her trusty dehydrator. Let's explore why these cooking methods make so much sense.

SteveBaxter a la sous vide

SteveBaxter a la sous vide

Sous vide, a convenient, hands off means of cooking, is French for "under water." Mommie uses an immersion circulator named "Yummy" to heat a big container of water to a certain temperature. When the water is ready, she plops in a bag of vacuum-sealed food (like chicken or venison or fish), sets a timer and gets back to playing with me. One time, Mommie put me inside the sous vide container. Why are people so weird?

 

Anyway, the food is cooked at a constant temperature over a specific period of time, kind of like how pasteurization works. Mooooo! While no cooking technique is a guarantee of food safety, a little science goes a long way with regard to understanding how proper sous vide cooking kills harmful bacteria utilizing the inversely proportional, logarithmic relationship between time and temperature. Below is another link for further understanding of the sous vide process:

http://www.amazingfoodmadeeasy.com/info/sous-vide-safety/more/sous-vide-safety-salmonella-and-bacteria

 

Just checkin' out the treat situation :-)

Just checkin' out the treat situation :-)

Dehydration is an ancient method of food preservation in which food is dried to remove water, preventing yucky stuff like bacteria, mold and yeasts from growing and multiplying. Depending on the means of dehydration used, the nutrient value of certain foods can also be retained. Mommie is hoping to score a freeze-drying machine soon, which would be the bomb. For right now, she dehydrates her yummy dog treats at 165 degrees Fahrenheit for about 14 hours, until they are light and crispy. She then freezes them to keep them nice and fresh. Every time I hear the refrigerator open, I get super excited because...you guessed it...it means she's probably going to give me a treat! 

Here are some links about food dehydration:

https://www.extension.umn.edu/food/food-safety/preserving/drying/methods-for-drying-food-at-home/

https://en.biomanantial.com/dehydrated-food-dried-advantages-properties-and-procedure-a-2202-en.html

https://dehydratorblog.com/food-dehydrating-time-temperature-guide/

OK, whew, I'm all scienced out now and about to floof down in Daddy's lap. Although I'm just an adorably fluffy bichon frisé puppy, I do understand a thing or two about science. After all, my father was named Sir Einstein. Just like him, I enjoy knocking toys off the bed and seeing them drop to the floor. Gravity, y'all! Well, maybe that's a little more Sir Isaac Newton than Einstein but you see what I'm getting at. Although Mommie says making dog treats isn't rocket science, a lot of science goes into producing them. And science never tasted so good!

 

science is yummy!

science is yummy!