Hottop Analogue Vs Gene A Blow By Blow Account

Hottop Analogue Vs Gene A blow by blow account
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Just over a year ago I was invited to a demonstration of the GC. As a HT owner I was skeptical that the much cheaper GC could possibly be the better machine. After witnessing a few tests, I was so impressed that within a couple of months I had sold my HT and brought a GC. I was not alone in this judgment, another member of the forum also made the same upgrade. Listed below are the reasons for my decision.

The HT is a nice looking machine, nice and shiny. It looks like a scaled down professional roaster. It’s a pity though that the control panel looks like a part from a 1950’s sewing machine.

The GC looks a bit weird, with its off axis drum and curved lid – It looks like the kind of machine that might end up being left at the back of a cupboard next to the waffle making machine.


Much has been made of the "superior" build quality of the HT. I cannot understand this. Having replaced the element in my machine 3 times, I know what the inside of the HT looks like and it is not a pretty sight. Lots of unnecessary holes, cheap plastics and self-tapping screws, much like a cheap washing machine. The construction of the GC is very simple, a lot like a good quality printer rather than washing machine.

The HT is the more complicated machine, which in some ways justifies its higher price. However I disliked the fact that the rear fan draws hot, dirty smoke through the main drive motor. Although I have not heard of any failures of this component, it just seems like bad design. It also means that the rear of the machine should be removed periodically to clear the chaff. The GC is in my opinion exceptionally elegantly designed – with no comparable weaknesses.


In winter most people are forced to roast inside so the ease at which the smoke can be removed from the house is of the up most importance. The HT fails miserably in this respect. As an inevitable result of its design the chaff tray gets very hot, effectively burning – if not charring the chaff. This means that the machine has more smoke, and smoke with a stronger odor to dispose of than the GC. Having a fan at the rear of the machine as well as a vent on the top of the drum means that even if placed directly under a cooker hood, a large proportion of the smoke is blown horizontally across the room. The GC has only an upward facing vent – placed under a cooker hood a very large proportion of the smoke is removed. In addition Gene Café also manufacture an extra large chaff collection to which a hose can be connected to vent the smoke directly to the outside world.

The chaff tray on the older HT’s was not sufficiently deep, it was very difficult to remove it from the machine without spilling some. Carrying it across a kitchen to the bin without spilling some was a perilous affair. I am told that newer machines have a deeper tray, but even this cannot compare with the convenience of the fully enclosed filter box of the GC. The HT does a reasonable job of removing the chaff from the roasted beans but this is not nearly as effective as the almost complete removal achieved by the GC.

This is one area in which the HT scores over the GC. The HT is very quiet, it sounds like a good bicycle on a wet road - it is very easy to hear the start of each phase of the roast, making the judgment of when to end the roast very easy indeed. By comparison the GC sounds like a hair dryer, judging the start of each crack can be very difficult. However the GC gives a far better view of the beans than the HT meaning that it is easy to judge the state of the beans by their colour.

The HT’s cooling tray does an excellent job in cooling the beans rapidly after roasting. However dumping very hot beans on an open tray inside your house is going to create an awful lot of smoke. Exposure to this amount of smoke cannot be good for your or your families health. The GC is slow by comparison but probably no slower than a large professional roaster, and because it is enclosed there is no smoke, and no health hazard.


The membrane buttons on the basic HT are without doubt the worst examples of their type I have ever come across. If used outside even on over cast days it was difficult to see the LED’s. Worse, the pressure needed to operate them was sufficient to push the machine over. In order to operate them it was necessary to support the machine from the opposite side, potentially dangerous when the machine was hot.
The basic HT has 7 pre set settings, on my machine all but no.7 were useless ejecting the beans before 2nd crack. The Controls on the GC are very simple and light to operate and the machine very responsive. However, like the HT’ it’s difficult to see the display in daylight.

Both manufactures have economized on the control systems but I believe that Genesis has achieved a much better compromise than Chang Yue.

Before the roast can commence in the HT the machine must be pre heated – this takes around 4-5 minutes when a preset temperature is reached the machine bleeps indicating that the beans should be put in. From this point on the machine is in an open-ended control loop system. This means that there is no feedback from the drum to the control system. The temperature rise is controlled by switching the element on and off (over simplification) according to a pre determined pattern. This takes no account of ambient temperature, drum temperature or supply voltage.

Gene Café
The Gene Café uses a simple thermostat idea to control the roast. The user sets a temperature the machine then keeps the element on until this temperature has been achieved. To obtain a reasonably slow increase in temp Genesis have fitted an element that if on continuously gives a reasonable roast profile.

The problem with both systems is that variations in supply voltage and ambient temp can mean that the roast times become unacceptable. My problem with the Hottop was that even with loads of less than 200grams I was getting roast times of 20 minutes or more. The GC is far less affected by low voltage than the HT. My GC has always managed to roast 250 in less than 18minutes.

The HT is basically automatic. The machine follows its preset pattern until the user extends or ends the roast. The built in profile is inevitably a compromise. Ideally the heat input to the beans should be reduced around 1st crack allowing 3 to 4 minutes before 2nd. The machine cannot possibly know when 1st has been achieved and so reduces the heat input at a preset time. However if the supply voltage or ambient temperature is low the machine still reduces input power at this preset time. This results in very long roast times and “baked beans”. Conversely 1st may be reached early, but the HT may continue pumping in additional and unwanted heat.

The CG really comes into its own here. The operator is able to vary the power at will and can therefore reduce the heat input by a suitable amount at a suitable point during first crack. The variation in 1st crack times between different beans is huge. It is therefore of huge benefit to have manual control.

As indicated above the HT is basically automatic, it therefore requires very little knowledge or skill to get a decent roast. The GC on the other hand requires the operator to shape the roast profile. It takes time to master the GC and early roasts are likely to be much inferior to those obtained on a HT. However simply allowing the machine to ramp up to temp and ejecting as soon as 2nd crack is heard gives a result very close to that of the HT. See other articles on this wiki for details.

The HT requires the rear filter to be replaced every 30-40 roasts, at the time of writing these cost £13.95 each. If your coffee consumption is around 750grams per week ie 3 roasts per week this equates to about 4 - 5 filters a year. The filter on the top of the machine should be replaced after 100 roasts, say once a year. These cost £13.99.

So the minimum cost per year would be:-
4x£13.95 + £13.99=£69.79 (+p&p)

Over the lifetime of the machine, say 5 years
5X=£69.79=£348.75 (+p&p)

The GC does not require any replacement filters; the annual cost of ownership is therefore limited to the power it consumes.

As mentioned in the “control system” description, the HT preheats the drum before commencing the roast. What was not mentioned was that, after having completed a roast, the HT goes through its cooling cycle effectively cooling the machine down to room temperature before pre heating it again. There is no way of hurrying it up, it insists on cooling all the way down to room temperature between each roast. It is therefore around 25 – 30 minutes between roasts. In addition to this, the operator must empty the chaff tray between each roast or risk a potential fire. The GC on the other hand is perfectly happy to roast back to back, with no need to empty the chaff from the filter.

The Table below shows the roast time per roast

To roast a 1Kg of beans in the CG takes around 1.5hours to do the same with a HT running at 250g would take more than 3 hours.

It should be noted that the HT cannot roast a full 250g load in 18 minutes if the supply voltage is much less than 240 or the ambient temp much below 20deg C. Most users will find that to achieve reasonable roast times under less than ideal condition the load must be reduced substantially.

Well is there any need to spell it out? With the exception of noise and cooling, the GC wins on all the parameters listed above. For me the most important of these parameters is the ability to roast when the supply voltage is low, coupled with the ability to remove the smoke from the house. The superior roasting capabilities both in terms of quality and productivity, in addition to the low cost of ownership make choosing between these two very easy.