Oops, "comparable" was not a brilliant word choice. I didn't quite mean equal, but I wasn't trying to BS in the "Tonka trucks are comparable to Mack Trucks" type way.

The M3 is built more simply, is more serviceable, and uses heavier duty parts. It can be used for back to back roasts and can run a lot more roasts in a row without ill effects. You can drop the beans for the next load in while cooling the previous load (even with the heat and air off, the residual heat in the drum and roast chamber will handle the drying phase). You have full manual control, a tryer and analog gauges. It is built by enthusiasts like us and is somewhere between semi-commercial and full commercial in intent

The Hottop has profiling capacity built in. It does a nifty cooling stirrer, rather than the stir it yourself of the M3. You can't turn all the dials to 11 and let it self destruct like the M3. It is a built by people who know how to design high quality home appliances. It is the first home roaster with a spotless track record.

My point was that the M3 does not "knock out" the Hottop. Either roaster is still a good purchase, and now you have a choice depending on your preferred style.

The M3 drum looks like carbon steel, and holds heat like it. With pans, solid cast iron or carbon steel are very useful, while solid stainless is not; but small solid drum roasters do sometimes come in stainless, not sure why.

Thank you for the response gentlemen.

See, again two posts and two different drum materials... I am tempted to think that the drum is indeed Stainless steel...

The electronics and the programing capabilities of the Hottop are not appealing to me at this time. I would rather have fully manual and add the PID and profiling later if and when I feel like it.

I really want a strong solid drum roasting machine. I am getting convinced that the M3 might be worth the extra $300.

I think the drum is made of stainless steel. I have googled for stainless steel pipe and the pics look identical to the drum of the roaster.

http://www.traderscity.com/board/userpi...316l-1.jpg

http://www.pipe2002.com/imglibs/images/...28-big.jpg

http://www.stainless-steel-tube.org/ima...-Tubes.jpg

http://product-image.tradeindia.com/004...-Pipes.jpg

Cheers

A magnet should answer the question. If stainless steel it is most probably austenitic and non-magnetic.

Rob
NZ

Without checking any references (so I may not get this perfect), the family of stainless alloys once called the "300" series (304, 305, 316, etc.) has considerable nickel (and other stuff) in it and generally doesn't have any interest in magnetism. What was once called the "400" series of stainless has no (or little) nickel, but has chrome and other stuff, and gets to be called "stainless" (at least by the suppliers), and usually does know what magnetism is. So maybe the question is: "is it the good stainless (with nickel), or the cheap stainless, or neither?". -Ed

While it is true that most 400 series stainless steel have no or little Nickel, All stainless steel contains a minimum of Chromium.

Most, if not all, household application use 300 series stainless and this is the reason that it is widely believe that stainless is non-magnetic.

The series 400 is used for application where more hardness is required. It is not generically cheaper by any standard.

DRUM = non magnetic (but there is a very slight pull)
FRONT & BACK THICK PLATES = magnetic (strong pull)
DOOR COUNTER WEIGHT = magnetic (strong pull)
ROASTER SUPPORT BRACKET (hanger looking) = magnetic (strong pull)
EVERYTHING ELSE = non magnetic (no pull)

Cheers

Not judging this roaster, but there is stainless steel that does have magnetic properties, we use it in the food industry where we drive conveyors belt with magnets, the health regulation require it to be stainless steal, rather then zinc or galv. plating. So we sell certain customer stainless magnetic belts. It is called 430 stainless.

steamer wrote:So we sell certain customer stainless magnetic belts. It is called 430 stainless.

All of the 400-series stainless steels (410, 415, 430, etc.) are quench-hardened martensitic stainless steels that are indeed magnetic. The 300-series stainless steels (303, 304, 316, etc.) are austenitic, non-magnetic, and cannot be quench hardened.

But I would never use a 400-series stainless for a roaster drum because the heat exposure will change the properties (and the shape!) over time. If it is stainless then it is probably austenitic and non-magnetic.

The Magnetic test for S/Steel is bunkem one or 2 of the 300 series are also magnetic albiet it weaker.

There are some good reasons to use 400 series over 300 series as a general rule (ignoring a few strange alloys). Thermal expansion of the 400 series is similar to mild steel and MUCH lower than 300 series. If you made a drum from 300 you would need to have a larger clearance at each end of the drum to avoid galling in the ends caused by lower expansion of say a steel frame. Thermal conductivity is also much more like conventional carbon steels while 300 series is very poor for thermal transfer. The best one to look at would be a 410 for roaster drums based on my looking at Material data.

Apart from usual 3-4 times cost increase in production the only real reason to make a drum from S/Steel is a cosmetic one or if you are like me and live 200m from the Southern Ocean then there is a corrosion reason, rusty coffee is not my prefered brew