This will be my second review of the HydroPro-Plus. My first one was more about functionality, and I've wanted to write another one, but I wanted to use it a little more. I've owned it for about 6 months, and I venture to guess I have over 600-Hrs of use on the unit. Now that I've run it through its paces, it was time for another review.
I've used the Hydropro-Plus in numerous containers. After reading one of my earlier posts that touched on thermal conductivity and overloading a container, I wondered if Hydropro could mitigate those issues because of its design and power. I've conducted similar haphazard tests, but nothing that would foster me to write about, though.
First, let's check the specs:
Tech Specs
- Maximum Bath Volume: 45 liters (12 gallons)
- Maximum Pump Output: 17 liters (4.5 gallons) per minute.
- Maximum Temperature 194º F (90ºC)
- Temperature Stability: ±0.1º F (±0.1ºC)
- Heater Wattage 1450 Watts (120 V): 1485 Watts (240V)
- Flow Adjustable: 3 speeds.
GEEKY NERDY STUFF BELOW. SCROLL BELOW REDLINE TO SKIP.
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After studying the specs, I wondered what the results would be using different amounts of water and protein. Let me explain: We all know we use an Immersion Circulator to heat the water to a precise temperature, and after the heat transfer occurs, we have achieved a state of equilibrium.
Let's define some terms: Equilbrium= Food and Water are at the same Temperature. Temperture=Energy: Heat transfer occurs using the Energy from the heated water until equilibrium happens. Since we know, Temperature equals Energy, and when the Energy levels of both the food and water reach a state of equilibrium, the temperature will stop rising. Essentially this method of cooking or processing food is called Sous-Vide.
Thermodynamics and Heat: Consider this for a moment: I said earlier that Temperature equals Energy, but how did we arrive at that Temperature? Since I am writing about Sous-Vide, I will address it from that perspective, but it's not exclusive. Heat also is another form of Energy and takes place between two objects. The Vessel that holds the water and the Immersion Circulator that heats the water. The rise in Temperature caused by the I.C (Immersion Circulator) gives water Energy. The law of Thermodynamics dictates that heat only flows from hotter objects to colder ones.
Some Geeky stuff for you to ponder: The last 0.5-1℉ can make up about 15-30% of the whole time it takes to reach equilibrium. There are several factors, of course. Thickness, Diameter, and overall Mass. I.e., Protein measured 114.6mm (Cylinder); it took 05:16:00 to reach 0.5℉ degree of the target temp. The target temp was reached 67-minutes later. I.e., #2: A steak that was 73mm thick took 03:30:51 to come within 1℉ of target temp, but it took another 01:18:00 to reach target temp and achieve equilibrium.Super Geeky stuff... To avoid the issue with diminished heat transfer as described above, we use a method called Delta-T.
What is thermal diffusion? What is thermal mass? This subject on its own would require an overabundance of posts just to scrape the surface, but maybe a slight caress will suffice. I have to give homage to Dr. Douglas Baldwin because he covered a lot of this in his book (LINK). Read his footnotes and the appendix. I'll admit it's not an easy read meaning it's undoubtedly nontrivial and requires a deep dive.
Thermal diffusivity is a measure of the rate at which heat disperses throughout just about anything. Thermal Conductivity is a measure of how easily one atom or molecule accepts or gives away heat. In Sous-Vide Processed food, the idea behind thermal diffusion is the ability to calculate the rate at which heat diffuses through the protein.
Thermal mass is equal to thermal capacitance or heat capacity. All of these terms apply to the cooking method known as Sous-Vide. Think of Water and Protein.
Let's talk about thermal Conductivity for a second because this, too, applies to Sous-Vide cooking. Thermal Conductivity is the ability to transfer heat, which is directly related to food thermal properties. Food thermal properties (I am talking protein) are based on those properties that control heat transfer to a specific food, I.E., Most land animal muscle is roughly 75% water, 20% protein, and 5% fat, carbohydrates different proteins. Thermal Conductivity, Thermal Mass, and Thermal diffusion are all intertwined in Sous-Vide cooking.
Heating food with efficiency is an excellent place to start when you consider using Sous-Vide's cooking method. Choosing the suitable Vessel (Holds the Water) to match the Immersion Circulator power output is a good start. Always make sure the cooking Vessel is covered to avoid water evaporation. Most people don't know that evaporation has a cooling effect on hot liquids (evaporative cooling). I experimented a while back and put probes in two corners of the container with the lid off and noticed temp differences. Now imagine putting cold food in the container. I don't know about you, but I want uniform heat distribution. So do yourself a favor and cover the container. No cover? Use plastic wrap. And if you want to make everything more efficient, use an insulated container. I use a polycarbonate container, and on long cooks, I use blankets to insulate the outside secured with bungee cords.
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As previously stated, I've used the Hydropro-Plus in numerous containers. Ultimately this test was about thermal conductivity and overloading a container. I questioned if Hydropro could mitigate those issues because of its design and power. As always, one has to consider a suitable Vessel (Holds the Water) to match the Immersion Circulator power output. As an Admin/mod in about seven food groups, we preach never to overload a container and make sure you have adequate space between bags for the water to circulate. This time I will be overloading the container on purpose.
I'll attempt to keep the nerdy stuff out of the review, but it's doubtful.
It started out with me going to the store and finding chicken breasts that would work for this project. I got lucky and found packages that were just about equal in weight. I weighed out each chicken breast and divided them equally.
20-Chicken breasts divided into amounts of 10 weighing 3194g and 3190g. An electronic caliper was used to measure the thickness. I found two that measured at 41mm.
Three calibrated probes were used to monitor the temperatures in both containers. The Hydropro-Plus monitored the internal temp of the Chicken, whereas the
ThermaQ® Blue monitored the bottom. The probes at the bottom were strategically placed to observe the middle and far end temperatures. Note: If you have any questions about using a Probe with Sous-Vide, go to
Hydropro-Plus Website by Polyscience.
Two containers were used for the project. An 18-Liter (filled with 10-Liters) and a 64-Liter (filled with 40-Liters) and the protein displaced 3-Liters.
Before I continue, I want to discuss the setting in which the project was performed. It was about 91 degrees outside, and the ambient temp in the kitchen was 62f. 99% of the time, I always use many blankets attached with bungee cords to secure, but I did not use them for this inquiry. The containers were covered, of course, to avoid evaporative cooling and evaporation.
Note my SOP when adding lots of cold meat to a vessel is to hedge the temp by a few degrees, meaning I set a few degrees above target to avoid a drop in temp. This will vary between 2-8 degrees based on mass. For this project, I did NOT adhere to this SOP.
The Hydropro-Plus for both containers was set to 152f. In both cases, the chicken breasts were placed in the center in the middle of the containers.
It's important to point out that thermal diffusivity is dependent on a few factors. Species, but we are using Chicken. Of course, the muscle type too, but we are using breasts. Temp, of course, but we will use 152f. The amount of water is the issue, displacement, and overcrowding.
The test commenced using the 18-Liter overloaded container. Again the I.C was set at 152f. After the Chicken was added to the container, the temperature dropped immediately to 146.5f. The Hydropro showed 146.5, and the Thermoworks probes showed 145f. This sounds alarming wrong but not expected. Think about the thermal mass of the protein vs. the water. Anyhow here is the good news!!! It recovered in 7-minutes. The time to recover seems to be excessive, but believe me when I say it was not. I have a buddy that had a similar setup with a different popular I.C, and it took an hour to recover. During the cook, the Thermoworks probes were always within 0.5℉-1.5℉. It took 01:29:00 to reach equilibrium, but I kept it longer to pasteurize (about 15 minutes longer)
The chicken breasts were removed, and it happened to coincide with our lunch. I quickly chose four breasts at random and promptly shoved a Thermapen probe in, and the temps registered 148f, but this is because it took a bit to remove the bag and take temp. I was pleased and astounded with the results.
The 64-Liter container was up next. Same as before: Temp only dropped 1.5f, and it recovered extremely fast. ThermaQ® Blue probes stayed within 0.5℉-1.5℉ too. The Chicken reached equilibrium at 01:26:00, and I kept them in for about 15-minutes more. Note: Pasteurization at a 7d takes place at 152f in 2.3 minutes if using FDA Charts at 1% fat and if using Modern Cuisine Tables 48.38 sec and 44 Secs for a 6.5D. If you are geeky like I would want to know what Log Reduction I reached with an extra 15-Minutes. Well, it might surprise you, but it achieved 133D. For some perspective, a 7d is 10,000,000 to 1 pathogen reduction or 99.99999%. A 133D? Take a one and add 133 zeros or 133 nines.
Extremely impressed with Hydropro's performance!! From personal experience with this unit and my other six it the performance was topnotch!!
My analysis, measurements, and computations were all produced on things found in a typical kitchen. No scientific equipment was used, and thus the results could be imperceptibly flawed.
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