Tag Archives: Plus 8

Early July Update. Observation on SR500.

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Having been offered full time employment starting the middle of July after approximately 2 years of unemployment things are looking good for getting some progress on this project. LOL! While this may sound odd this is actually good due to the fact that I’m building (if all goes properly) a somewhat professional-esque coffee roasting computer. It takes a lot of money and resources to design this thing. I’m already into the project around $300-400 worth of circuit development kit gear and need a lot more stuff. In the end I’ll have a complete system that will be significantly cheaper to build but still have all the development kits to make other projects. I chose that route because of the “other projects” for down the road instead of only buying the things I need right now. While having full time employment will limit my available time it DOES however allow me money to keep purchasing all the parts.

Most projects you find on the internet for a coffee roaster use something like a Basic Stamp or some other very limited processor. It also usually involves hooking together a few things someone finds off eBay hooked together with some various wires and connectors salvaged off some old computer equipment and other devices abandoned in the garage. By the time it’s done you get a picture on the internet of some “finished” popcorn popper that looks like it’s about 30 seconds from taking out a corner of your house into a huge crater or like it’s some sort of industrial wiring project of conduit and electrical boxes.

I’m intending on making this thing as small as I can make it and sealing it up inside a electronics case with a single cord or perhaps a cord and a sensor wire that plugs into the back of the case that leads to the roaster. I don’t want 50 million little cords and sensors and clunky switches and other doo-dads spread across my counter. I also want to be able to pick the whole thing up and move it somewhere else without accidentally cracking off a wire and needing to re-solder it. I don’t know about you but I love my coffee. I don’t love having to re-solder the wiring just to roast some more or being unable to use my kitchen for anything else.

My Kitchen is not that big. It cannot accommodate a lot of “stuff” strewn around it. so the entire thing will need to be compact. As a result I intend on having a case that has a LCD touch screen installed. It will probably have a LED or two and at most probably a single power switch on the front edge or side. I will likely try to design the circuitry so that it fits onto one or more circuit boards stacked on top of one another. The LCD will be mounted on top with various connectors and other items stacked below it. I’m reasonably sure I can shrink the majority of this down into a space about 4″ by 6″ and about 1.5 to 2″ tall.

As mentioned I recently purchased the PIC32 development gear. At the moment I’ve been working on the GUI. This is a lot more complicated programming than I’m used to. Additionally I’m having a few “weird” situations where LED’s on the starter kit are lit that I don’t seem to understand why. When I turn on an LED that is normally off things work fine but then when I programmatically turn that one off the LCD turns off too though they shouldn’t be connected at all. The other LED works fine turning it on and off the same way. One of these LEDs simply stays on all the time no matter what.

At the moment I now have a “splash screen” functioning. I touch the screen and it continues to a “Home” menu. From there it offers several buttons to run the manual or the automatic roasting menu. There is also a provision for a Setup menu. I am still waiting for the ethernet to arrive that will allow me to download roasting data out of the system or pre-configure a roast from a web page. It currently draws temperature onto the screen from some “made up numbers” I have the thermocouple and the chip that will convert the sensor reading to numbers but need to solder it to a board that I can connect to the processor. I also need to do the same with the clock chip that I have as well. The processor has built in clock routines but they only work while the system is turned on. As soon as you cut power that clock loses it’s data. As a result I will program the system to read the clock chip every time the system turns on.

Over the next few days I will program the roasting screens to change certain display areas based on the simulated temperature numbers and then integrate the “control” portion where it then stops the increase in temperature and then tries to increase it appropriately. I still need to figure out the timer stuff… it doesnt seem to run on the demo and I was thinking it had to do with an oscillator being missing but this seems to be related to USB stuff in the documentation for the starter kit. This doesnt seem right though. I need to figure that out and then the next step is to start ordering all the pin headers and not included on some of the other boards. I’ll try to figure out a few more of the parts that I’ll need and order those in the next few days as well so I can keep working on this. Assuming I’m right that the crystal is required apparently Microchip decided to save 83 cents by not including the oscillator.

Also as a side note. Due to the job offer I completed a move to Northern California from Central California which has kept me from messing with the coffee much until now. A variety of coffee that I roasted here with the Fresh Roast +8 took approximately 6 minutes to hit second crack. Using a SR500 where I used to live took about 6 minutes as well while running the fan at half speed for the first two minutes. To do the same thing here with the SR500 appears to take around 7-8 minutes with a lot more slowing down the fan to around the 25% setting once movement starts to flow more easily and first crack was reached.

Fresh Roast SR500 First Impressions

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So as mentioned in the first blog I received a Fresh Roast SR500 roaster today.  I had been tortured by having coffee roasted in my girlfriend’s Fresh Roast Plus 8 while visiting her and then coming home to coffee out of a can and occasionally the whole bean stuff from the grocery store from my landlord that I rent a room from.  I brought a couple pots worth home after one trip to let me have some good coffee for an extra day or two as well as to introduce it to my landlord.

Like me she instantly saw how good it was compared to the usual stuff and she got interested in the process of roasting at home.  We watched the various videos on YouTube and reviews produced by those at Sweet Maria’s, Coffee Geeks, and a variety of other places.

The Fresh Roast Plus 8 that my girlfriend has and the Fresh Roast SR500 are both somewhat similar machines.  There is also a SR300 which is a less featured version (compared to the SR500) that is also available.  The Plus 8 and the SR300 are technically feature identical since both allow you to set the time only.  All three models have a specified number of minutes and then proceed to a “Cool” period at the end.  The SR500 has the addition of a switch to control the level of heat and a knob to adjust the speed of the fan.

Since I have only viewed an “in-service” Fresh Roast Plus 8 I cannot comment on the original packaging.  The SR500 arrived in a white cardboard box with various marketing type details written on the side.  Inside the box packed in white styrofoam was the SR500 roaster.  This includes a small manual, a small plastic scoop wrapped in a plastic bag, the roaster’s chaff collector, the roasting glass chamber, and the base.

Upon removing all of the parts from the Styrofoam packing I found all of the parts to have small little Styrofoam “dust” / pieces static stuck to the various parts.  As a result I needed to dampen a sponge and wipe off most of the parts or rinse them under a faucet (uhh no rinsing the base please… electric parts and water do not go together)…  Once everything was wiped down I then began to inspect all the various parts.

The Chaff Collector
This part of the roaster is significantly different than the Fresh Roast Plus 8.  I will start describing the Plus 8 and then moving on to the SR500.  The Plus 8’s top is entirely plastic with a screen inside the top part.  The top of the roaster slides down on top of the bottom part overlapping.  The plastic is entirely made from a high temperature plastic so that it does not melt.  It has a feeling of being somewhat light and somewhat inexpensive if not “cheap”.

The SR500 on the other hand also seemed to be a high temperature plastic and cosmetically looks slightly similar to the original Plus 8.  When you pick it up the top of the SR500 appears heavy and somewhat substantial in comparison.  The top is very shallow due to it no longer overlapping the base.  Here it is shown upside down…

The screen appears to be held in by a variety of metallic washers against small plastic “nubs”.

In the center of the lid behind the mesh is a 3 inch (roughly) metallic disc that appears to be similar to the metal used for bolt washers sold in the hardware store.

This provides a lot of bulk that appears to hold the lid on instead of allowing it to blow off.  More on this disc later.  The bottom of the chaff collector cup portion has a similar slotted opening over the roasting chamber to the Plus 8.  There is a sort of angled design to the slots that is different from the original Plus 8.

The top fits to the bottom with a small edge that appears very sensitive to proper alignment as well as proper creation of the plastic pieces when it is injected into the moulds at the manufacturer’s facility. The top piece has a matching groove on the inside to fit.

The top fits over the top of the roasting chamber… but not very well without some effort.  (Notice the gap on the right.  It takes some (minor) effort to get everything to fit snuggly)

The Roasting Chamber
The roasting chamber appears to be maybe 25% wider than the original cup if not more.  I have not measured it but this obviously has to do with the increased capacity of the SR500 from the previous roaster version.  The handle is held on similarly to the original roaster using a metalic band attached to the handle.  The handle on the new roaster is less solid feeling using much less material.  It also gets somewhat warm if not hot to the touch after a full roast.   In addition the metallic base is made from much thinner material… the same as the band on this roaster.

The last base was a thick cast metal base with a glued in round hole screen.  The new roaster has a base that is all one piece pressed from material that appears to be similar to the previous screen.  This results in a less robust feel to the roasting chamber.  I would postulate that this lighter material at the base, however, helps in the cooling cycle by having less metal mass to hold heat near the beans at the end.  Further inspection of this base shows it to be very shallow compared to the last roaster.  The old metal base was much deeper than the current base causing more of the beans to be “hidden” during the initial part of the roast on the old roaster but also allowing the cup to be more firmly seated in the roaster base.

The Roaster Base
Now on to the base…  This is where the most substantial differences are.  The old roaster was perfectly round with a knob that you turned to set the length of time or slide it to cool.  With the new roaster you have a digital “up” and “down” button to increase the time in .1 minute (6 second) increments.

When you start the roaster it starts with 6 minutes immediately dropping to 5.9 on the red LED display.  On the SR500 you start the roaster by sliding the switch to Low, Medium, or the High heat setting.  You raise and lower it by pressing the up and down buttons and can force it to cool by pressing the cool button.  This switches the heat element off into a cool mode running the fan only.  The fan sound is significantly different than the previous Plus 8 roaster.  It is of a different sort of pitch and seems quite loud compared to the Plus 8 though I cannot be sure without running them side by side one after the other. Unlike the SR300 which has only one fan speed the SR500 has a variable knob.  Lowering the fan speed to the middle position on the knob it seems possibly similar to the old roaster.  Due to the much wider base of the roast chamber to accommodate more beans more air is needed to churn the beans.

The wattage on the base is listed as 1600W for 120V.  The model number appears to FB102SR.

Roasting
This roaster seems to thus be more sensitive to being on a solid, level surface.  I have seen several people complain that it does not churn the beans enough resulting in burning.  In the instructions it says to run the beans (if necessary) initially by using the low heat setting with the fan on high.  What I found with an initial roast is that this is an important step until you see significant movement.  With my surface being very level the beans initially had good movement similar to that found in the Fresh Roast Plus 8 and an acceptable churn when set on low heat with high fan.  As the beans began to turn amber in color I then switched the heat to high.  It took approximately 1.5 to 2 minutes for the roaster to reach the amber coloration and the beans to begin to have a more rapid churn.  Once the heat was raised to high I allowed the beans to continue to roast eventually lowering the fan speed to around the half way point until first crack was reached.  At this time I slowly increased the fan until second crack and returned the fan to high during the cool cycle.

One of the drawbacks to the current configuration is you need to purposely remember to return the fan knob to high when you go into the cool cycle.  Otherwise the configuration seems to work well enough as is.  I think this model would be somewhat confusing for a first time roaster for them to figure out what to do and when in response to the roast.  It seems (from other reviews) that the SR500 has a higher fan output than the SR300 at the high setting and my used middle setting being the standard speed on the SR300.  I would consider that to be critical / mandatory making the SR500 the suggested model and thus making this tougher on a new person.  New people should concentrate on running the roaster on high fan and low heat until they see color changes happening as described or a lot of height in the beans being moved.  Once that happens they can dial down the fan speed and increase the heat to get a roast going.

Regarding the smoke from the roaster I have perceived this to be similar to the smoke from a Plus 8 roaster even with the increased capacity.  I didn’t set off the smoke detector but it is pretty obvious you’re roasting coffee inside the house.  You do want to run an exhaust fan while roasting typically with either roaster but it is not significant amounts of smoke.  The roaster does seem to cool down somewhat quickly MOSTLY.

Dealing with the finished roast.
As I mentioned earlier I was coming back to the chaff collector.  Due to the metal disc in the lid of the chaff collector there is a significant amount of heat retained in the lid for a much longer period of time.   This makes dumping out the chaff collector somewhat difficult right away meaning you need to let it cool for a while.  Due to the increased capacity of the roasting chamber you have more chaff collected up top.

The change in the angles of the strainer in the chaff collector do not appear to make much difference in the chaff passing through to the collector.  Most of the chaff appears to stick well into the collector, however, and you end up with similar amounts of fallen bits of chaff on top of the roasted beans that need to be blown out if you do not wish to get any excess in your grind. This roast typically only had a thin ring around the edge in the first picture which is now completely blocked up possibly due to the extra capacity.

The cooled beans are lightly warm and seem to be a few degrees cooler than the Plus 8.  This is possibly due to the cool cycle being digitally timed rather than controlled by a physical timer knob on the Plus 8.  On the Plus 8 the knob does not have any sort of positive confirmation that you are in cooling or heating as you turn it so sometimes you might short the cooling cycle a few seconds while with the SR500 (and 300) you will always have the same cool cycle by pressing the cool button.

At this time I have some beans resting in an airtight container until tomorrow after my initial roast attempts.  These roasts were done “by eye/ear/smell” and later in the week I will dig out my scale and try to get “scientific” about this as I work through the various sample coffees.  For now I just need decent FRESH coffee rather than the swill from a can.