Hands on Review: Robobrew All Grain Brewing System

This review is by Homebrew Finds Contributor Brad Probert.  Brad is an engineer, expert homebrewer and experienced reviewer.  Grab a link to Brad’s website at the end of this review.

The Robobrew is an electric all-in-one eBIAB system. It allows you to brew the complexity of all-grain batches with the simplicity of electric heat/control in a single vessel system. There is a wide variety of these systems out on the market to choose from. Robobrew aims to be in the midst of these as far as features and function, but at a much lower price to attempt to get this tool in the hands of as many homebrewers as possible.

Robobrew System Overview

The Robobrew comes in 2 models- one with a built-in pump, and one without. The model without the pump retails for about $350, and the one with a pump for $480. Although a significant price jump, the $480 price tag is several hundred cheaper than its competition. Getting a unit with a pump allows you to take advantage of a lot of the process efficiencies from the eBIAB systems, with convenience of recirculation during mash and pressure-fed wort transfer into your fermenter.

The pump is built into the bottom of the unit, tucked away out of sight and out of the way. There is a stainless steel transfer pipe that takes output flow from the pump and sends it up top where it can be directed to where you want it to go. The pump inlet is through an opening in the bottom of the brew chamber. Also in the bottom is the wort temperature sensor and the two independently switched heating elements (1000W + 500W). Although the heating elements have their own manual on/off switch, the unit’s electric controller also has the ability to shut off and turn on power depending on measured mash temperature compared to your set temperature. Importantly, the controller is smart enough to know when it should be using one or both elements when it’s getting close to your set temperature. It also is smart enough to only switch on the 500W element while trying to hold a steady temperature and things start to drift a bit.

For mashing, you put your crushed grains into the stainless steel malt pipe, which has a false bottom mesh on the bottom of it to keep grains from getting circulated into the pump or scorched to the bottom. There’s also a second false ‘bottom’ screen, which slides down inside the malt pipe after you’ve filled it with your crushed grains. And if two false bottoms aren’t enough for you, Robobrew has you covered with a third false bottom that sits below the malt pipe, giving you another layer of defense against stray grain particles during the mash, but also importantly keeps hop residue from clogging up your pump or wort chiller.

The controller provides basic control function by allowing you to set a target temperature with simple + / – buttons and then letting the controller turn on the elements automatically to heat up and then switch off when the target temperature is reached. There is also a delay feature that allows you to program in a delayed start for when you want the target set temperature to kick in. Set it to something short like a few minutes and make a pseudo mash temperature step profile you program one step at a time. Or for longer times (up to 24 hours) if you want to fill it with water and have the unit turn on to be ready for you after work.

Hands on Trial

Brewing a couple of batches in the Robobrew helped me get a feel for how to work with it. For certain, it was straightforward to use, and mechanically sound with good controller function. However, it did require some compensations on my part. I noticed on my first brew day that as I poured 7 gallons of distilled water into it from seven 1-gallon jugs, that the embossed volume markings showed 7.3 gallons. That was a bit disappointing, but I just learned to compensate by noting the volume markings and doing the 0.3 gallon math. Contacting the folks at Keg King about this, they noted they had already discovered this issue with some units and had made adjustments with the welding set-up to ensure when the sides of the unit get welded to the base, they line up at the appropriate spot for the volume markers.

The other adjustment I had to make was in the temperature reading. The digital controller read out a temperature on the display that you might assume is the temperature of your mash. But a check with my calibrated thermometer showed the Robobrew was reading about 5-7 degrees hotter than what I measured in the bulk of the fluid. I had some discussion with Keg King about this and basically it comes down to sensor location (on the bottom of the brew vessel, where the heating elements are) and what they were really trying to accomplish with the sensor. Specifically, they wanted to ensure they were reading the hottest part of the mash so as to avoid unintentional scorching down by the elements. In the end, I’m not sure this gets accomplished, because I just did the math and set a higher target temperature. If I wanted the strike water to be 155 degrees, I knew to set the controller to 155 + 5 = 160 degrees. With this adjustment in mind, I would manually set the controller temperature to a setting using my offset and then monitor with my manual thermometer.

False Bottom Filtering Hop Trub

The false bottom that’s left in the vessel after you remove the malt pipe really did work awesome as a hop filter for the pump. Even while brewing a hop-heavy IPA, I didn’t have any issues clogging things up in the pump. And the thick green layer of hop residue on the bottom after I had drained and transferred everything to the fermenter made it clear why that was. The built-in pump was handy to have for pumping wort through my counterflow chiller and then into the fermenter. Although the Robobrew comes with a standard coil immersion chiller (in shiny stainless steel), it doesn’t come with all of the necessary fittings and hoses to make it ready to go out of the box. That was fine by me because I didn’t have need of or want to use a coil immersion chiller. As with all of these electric all-in-one eBIAB systems, clean-up was easy and nice having just the single vessel.

Temperature Measurement Experiment

Wanting to better understand the temperature offset, I set up a couple of experiments where I compared the temperature reported by the Robobrew to that which I measured with my calibrated digital thermometer. I did 2 trials with water, one at a smaller volume (4 gallons) and one at a larger volume (7 gallons). These 2 volumes represented roughly what I’d use for a 2.5 gallon batch and a 5 gallon batch. You can see from the plots that both of them have a difference between what the temperature sensor is reading from the bottom of the vessel to what I was reading with my thermometer in the middle of the fluid. The difference was greater with the 7 gallon test than what I saw with the 4 gallon test. I also did a test where I took the 7 gallon volume and set it to hold a steady 152 F for a longer period of time. While I saw the same basic temperature error trend, the controller would switch on to try to control to the 152F, and as a result it held a constant temperature to within a degree during my 30-minute test.

My takeaway from these experiments was that I would need to factor in an offset when programming target temperatures. The temperature sensor error was smallest in the area of typical saccharification rest temperatures (~152 F), which was good. As other rest temperatures are perhaps a bit more flexible if I were to use just this 152 F temperature adjustment and apply it to any other mash step set points. Keeping the pump running to recirculate did a good job of keeping temperature steady and the controller was smart enough to just selectively turn on the 500W burner when needed if the temperature started to drop. This helped keep it from doing drastic swings. Armed with this data and a better understanding of the system capability, I feel my next brew session will go much smoother knowing how to adjust my target temperature and the ability for the unit to hold temperature well.

7 Gallon Temperature Test with 30 Minute Rest

More Temperature Tests

 

Summary

The Robobrew hit the mark for providing all the same functionality as its competition. It has some advantages like the second false bottom to prevent pump clogging and the delayed start timer, and comes in at a very affordable price compared to its main competition. There are some compensations you have to make with volume markings (if you get a unit like mine) and temperature set points. And although it has an overall good quality appearance, there are spots where you notice the thinner metal gauge in things like weld spots, trim edges, and part handling susceptibility to damage. But altogether, these items are relatively minor, and at the price of $480 compared to $890 for a similarly-equipped Grainfather model, it quite simply puts electric brewing within reach of a lot more folks. And that’s a good thing.

More Photos

Robobrew Immersion Chiller Coil

Robobrew filled with 7 gallons of water, but reading 7.3 gallons

Boiling Wort in the Robobrew

Special Thanks to Keg King with the help of MoreBeer for providing the unit used for evaluation in this review

Check out Brad’s website – beersnobby.com

Pinned: 3 Tap Tower | $7 Cascade lbs! | Robobrew Review | Pumps | Spreadsheets

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2 thoughts on “Hands on Review: Robobrew All Grain Brewing System

  1. Brad Probert

    Good question, and I’ve got a complicated answer. I won’t propose to have it definitively sorted out yet after only a couple brews, but here are my thoughts on this. It all revolves around the temperature sensing/control.

    1. Robobrew has the temperature sensor placed & calibrated to read the mash temperature next to the heating elements at the bottom. So if you’re setting your mash temperature based on the wort temperature in the middle of your vessel, your digital readout and controller will be reading high.

    2. Conceptually the recirculation flow should help mix the fluid better throughout, but it is also fighting against heat loss of the wort as it travels up the recirculation pipe. I found that the cool-off effect of this was significant when measuring with my own thermometer and instead of my bulk temperature going up because I was scooping hot wort from the bottom and dumping it up top, I actually got the bulk temperature going down as I recirculated. To me, this says I’m losing more heat through the recirc pipe than I’m seeing in temperature differential between the center of the mash and the bottom of the vessel. But there may be other explanations.

    3. The concept of recirculating to keep everything even and on temperature runs into issues because of the difference between what the controller is controlling to (temperature at bottom of vessel) versus what I want to control to (temperature in middle of mash). So if you recirc and successfully redistribute heat, your heating element won’t kick on until a point where the temperature in the middle of your mash is much lower than you want.

    Based on the above 3 points, here’s how I concluded was the best way (for me) to approach it. Set the controller target temperature 7 degrees hotter than I want the mash to be. Once it reaches temperature and the elements kick off, stir it up with a mash spoon to get good fluid distribution and then measure the temperature. If I’m good, wrap the whole unit in an insulating layer (I use an old down-filled winter coat) and be sure to cover the open hole in the lid (which I overlooked on first attempt) and let it just rest/mash. If it’s too hot, run the recirc pump while monitoring the temperature with my own thermometer until it reaches target temp and then turn it off and wrap in insulation.

    I’m concerned that if I constantly ran the pump during the mash, I’d be constantly cooling things off through the transfer pipe, and I wouldn’t get the heating element to kick on at the right point because it was worried about the temperature of the wort at the bottom next to the elements that were still cooling down, and as a result I’d get big swings in my mash temperature.

    Reply
  2. Joe

    Thank you for the review. I have one question about the following statement, “A nice thing about the recirculation pump is it could be used to easily adjust mash temperature. I found that if the trusty 7 degree temperature offset didn’t exactly work out and I ended up with strike water or wort that was too hot, I could just kick on the recirculation pump and watch the temperature drop fairly quickly (about 1 degree a minute).”

    Wouldn’t the pump just be on the entire time during the mash? I was kind of hoping that this would be the case and would help stabilize temps.

    Thanks.

    Reply

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