Ratio Eight Brewer Review

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#1: Post by HB »

Nearly all of the site's reviews to-date have been either espresso machines or espresso grinders. But with the membership's increased interest in other brew methods, this review features the Ratio Eight brewer, a precision brewer that automates the process of a manual Chemex brewer. Unlike the utilitarian combination of stainless steel, glass, plastic and more plastic that characterizes nearly every home brewer, the Ratio is housed in a cast aluminum shell with anodized finish and accented with real wood:

It has no switches or knobs. To maintain the smooth one-piece look and eliminate moving parts, the start brew switch is touch sensitive. Similarly the carafe has a cork bottom with embedded magnet that the base unit uses to detect if the carafe is absent or if it's removed mid-brew. If your appreciation of art leans to minimalism, the Ratio is certain to complement your kitchen decor.

The above "press packet" photo captures the Ratio's simple lines and uncluttered fascia, but belies the brewer's unusual height (14" or almost 2" taller than the Bonavita BV1900TS). Most US cabinets are 17.5 to 18" above the countertop; the photo below shows the Ratio Eight next to the Baratza Forte below a cabinet with 18" of clearance:

Of course there's still more than enough clearance above the brewer; the above comparison is simply to show that while the Ratio Eight borders on a modern kitchen's objet d'art, like the typical fashion model, it's noticeably taller than its less striking contemporaries.


As the name implies, proper coffee extraction requires a proper ratio of water to coffee (and of course, proper grind setting). The Ratio water reservoir has halfway and full line marks, though I recommend weighing the water/coffee, as it's easy to under or overshoot the desired water amount by going a smidge above or below the line. If you use a scale, remember to allow for the weight of the carafe itself. I use a Bonavita 3KG scale, though there's plenty of scales that can do the job recommended in the forums. The SCAA recommends a 18-to-1 ratio of coffee to water (or more precisely, 55 grams of ground coffee per liter). Although the scale is optional, of course a grinder isn't. For the tests at home, I use a Baratza Forte.

The Ratio includes a KONE permanent filter; it you prefer, it accepts paper filters, as does any Chemex brewer. The grind setting on the Forte was Macro = as coarse as it goes. The micro setting was adjusted such that the water collected on the bed of coffee but didn't overflow. For the coffees tested, I started around the midpoint of the micro setting and adjusted a couple notches. The brewing begins with a brief bloom phase where a small amount of water saturates the coffee bed then waits while the grounds expands; the brewing phase follows shortly thereafter. The full cycle is automatic and takes only a few minutes. The slowly bubbling water column in the reservoir offers a little coffee theater as it progresses.


Below is an excerpt from the SCAA's Minimum Certification Requirements for Coffee Brewers (download PDF):
  1. Coffee Volume: The volume of the brew basket must be sized in proportion to the beverage receiver's maximum capacity as stipulated by the manufacturer. Minimum technical requirement is for brew basket capacity to accommodate the Golden Cup Ratio weight of coffee per maximum capacity (~55 grams per liter) without overflowing from the basket due to the swelling of the coffee grounds during the brew cycle. This allowance should be about 50% of the bed depth of the coffee. Best results in uniformity of extraction are obtained with coffee bed depths between 2.5 and 5.0 cm, but these dimensions are not a requirement for the certification.
    • Brewing Time: The coffee brewer must be able to cycle its full-capacity water volume through the coffee grounds within the prescribed amount of time. For a brewer at maximum coffee and water capacity, the minimum technical requirement is for the water contact time with the coffee grounds shall be more than 4 minutes but less than 8 minutes for all brewers operating under standard temperature and pressure at the manufacturers stated design voltage, depending on grind. Under no circumstances will water contact times in excess of 8 minutes be acceptable in meeting the certification requirements.
      • Brewing Temperature: The coffee brewer must be able to cycle the gross water volume through the coffee grounds within the prescribed temperature range. Minimum technical requirement is for the water temperature at the point the water contacts the coffee grounds to reach 92°C within the first minute, maintain at least that temperature (92°C) for the remainder of the brew cycle, and never exceed 96°C. Measurement of brewing temperatures will be made by using an RTD (Resistive Temperature Device) placed at the top and in the center of the bed of coffee in the brew basket.
        • Beverage Preparation: The coffee brewer must be able to produce a beverage with the prescribed range of solubles concentration and solubles yield. The brewer will be evaluated at stated full capacity as well as at the 1 liter brew water volume. In situations where 1 liter is the maximum capacity of the brewer, the 0.5 liter brew will also be tested. Testing will begin with a coffee/water ratio of 55g/1L, but will be adjusted depending on the grind and contact time to produce a brew within the Golden Cup zone of the brewing control chart. Minimum technical requirement is for a beverage strength (solubles concentration) of between 1.15% and 1.35% resulting from an extraction (solubles yield) of between 18.0% and 22.0% from the weight of coffee in the brew basket, as determined by a coffee refractometer and brewing control chart. All samples measured on the coffee refractometer are filtered prior to measurement. The grind of the coffee will be adjusted for the water contact time of the brewer in order to achieve these results whenever possible, within the specified grind parameters (see below testing procedures). Brewers must be able to meet these requirements at both full capacity and a 1 liter capacity in order to be certified by the SCAA. Brewers with the full capacity of 1 L will also be tested at 0.5 L.
        At the time of this review, the Ratio Eight was not a SCAA Certified Home Brewer.
        Dan Kehn

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        HB (original poster)

        #2: Post by HB (original poster) »

        Next up, the results from our group taste test of the Ratio Eight and Bonavita BV1900TS...

        Dan Kehn

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        HB (original poster)

        #3: Post by HB (original poster) »

        At our regular Friday morning get-together at Counter Culture Coffee, we held a group taste test comparing the Ratio Eight and Bonavita BV1900TS. The first round featured a Colombian coffee called Kuichi (the name of a collective of 22 farmers). We used the VST refractometer to confirm the total dissolved solids were within SCAA brewing specifications. For the blind taste test, we used another coffee that would be more revealing, an Ethiopian coffee, Olke Birre, named after the farmer who grew it.

        The setup was simple: We brewed the coffees simultaneously and served them in identical cups. The bottom of the Ratio's cups were discreetly marked with a Sharpie. The pourer randomly placed cups in pairs and a server served them in pairs, randomly using their left/right hands, to each participant. The taster simply placed their cups on the table in the win and lose columns as they preference dictated:

        After everyone had placed their cups, the grand reveal:

        We were really surprised to see a clean sweep in favor of the Ratio Eight. :shock:

        Counter Culture Coffee had recently spent weeks evaluating brewers to decide which to carry and the Bonavita was selected as an ideal value choice. We considered possible reasons, notably that we intentionally used Chemex brew receptors and KONE filters, which of course isn't the standard configuration for the Bonavita. We decided to repeat the round, this time with standard configurations (i.e., stock KONE filter and Chemex for the Ratio, paper filters and basket with coffee decanter for the Bonavita). There was even talk of checking the level of the Bonavita since one participant noted it did not drip as evenly as he expected.

        While the second round wasn't a clean sweep, the Ratio was the clear winner 5 to 1. Some participants retasted the samples as they cooled; nobody changed their votes. Below are the participants' comments:
        Walt wrote:I would start out by saying both the Ratio and Bonavita brewers make excellent cups of coffee and the Mocha Master being the only other brewer I would place in their league. By starting the tasting with batches from both brewers one after the other with the, Counter Culture Coffee, sourced from Narino, Colombia I did not think there was any difference in the brewers and was taken with how great the coffee tasted. With the first blind side by side comparison of a different coffee, the equally impressive Olke Birre, single farmer lot from Haru, Ethiopia; really brought out the difference in the brewers. In an effort to control variables, Jesse switch out the Bonavita brew basket and pot with a chemex and Able filter, as comes stock with the Ratio. There was no question the Ratio brewed a superior cup. I tasted a flat papery (without the paper) mid palate with a drying finish from the Bonavita. The Ratio brought out the fruit note and sweetness of the coffee and had a very clean juicy finish.

        The next batch was done with the Bonavita's flat bottom basket and server, the blind comparison was much closer but I still preferred the taste of the Ratio. I revisited the coffee's after they had cooled and still chose the Ratio, however they were even closer in taste profiles at that point. One note, we did notice the Bonavita brewed faster, less overall contact time of water to coffee particle.

        I own the V1 version of the Bonavita, with the cone filter basket, and would still vote it the best value. (Disclaimer, I brew manual pour over every morning, my wife loves the Bonavita) However, the Ratio did win the taste off and if I needed to replace the Bonavita I would have to give it due consideration. The only remaining issue for me would be to ensure it can fit on the counter under the kitchen cabinets.
        Nathan wrote:when the test used a Chemex for the carafe in the Bonavita
        • Ratio: sweeter, more-complex flavor = clear winner
          Bonavita: paper-y smell + taste, uneven extraction (over-extracted in some parts of the bed, under in others)
        when brewing "out of the box"
        • Ratio: consistent from previous results = slight winner
          Bonavita: much closer in flavor to the Ratio; some extraction issue from dispersion unevenness
        Tyler wrote:Ratio was the obvious winner during the first round. This wasn't as surprising as the second round - I say this because we tend to think about home brewers as more stable in terms of the variables that come into play during the brewing process. Besides grind, water quality, and quantity of coffee, the other variables are controlled by the brewer itself. Yet, the second round was much closer contest between the two brewers (even though Ratio was still the clear winner for me - such a clean, sweet cup). Obviously a part of this was because we used the recommended paper filters for the Bonavita. But I also think that this round was effected by the Bonavita not being level on the table and was pushing water only through a couple of spouts on one side of the brewer leading to over-extraction which we were tasting in the cup. The level of the table or surface which the brewer is resting is not a variable we tend to think about - even less so for a typical home consumer. Demonstrates the overall challenge of creating the perfect home brewer at a price point that doesn't break the bank. Which leads me to my final thought. While the Ratio produced an excellent cup of coffee - is that excellent cup worth an additional few hundred dollars?
        Jesse wrote:In the blind test between the Bonavita Brewer and the Ratio, I found both to make great coffee, but the Ratio definitely had the edge. The two were much more closely matched when we tested them with their intended brewing setup (the flat bottom filter for the Bonavita rather than the Chemex), but the Ratio consistently produced coffee with better sweetness and balance.

        The big question for me is whether the price difference is worth the investment for the Ratio versus the Bonavita Brewer. Personally, if I were purchasing a brewer right now, I would still have to go with the Bonavita given the choice. However, if money weren't a factor I would definitely choose the Ratio. It's a beautiful machine and is expertly crafted. While not being able to predict the future and the Ratio's reliability, it seems to be built to stand the test of time.
        Although our taste test was only two rounds, I didn't expect such a lopsided result. Then again, as Tyler and several others noted, they both performed admirably, brewing a deliciously sweet cup. It just happens that for this particular test, the Ratio Eight was just a tad sweeter. :)
        Dan Kehn