Hottop 2K+ Continuous Roasting With Limited Cooldown Is Possible- With A Caveat!

Discuss roast levels and profiles for espresso, equipment for roasting coffee.

#1: Post by DSNORD »

Continuous roasting with limited cooldown using an unmodified Hottop 2K+ is possible- but it might gunk up your motor requiring a repair. Here's my story:

My Hottop 2K+ is about 4.5 years old and has about 275 or so espresso roasts under its belt. It has been a solid performer to date. Batch size is usually 225 grams in order to get 2 roasts from each 1 pound bag I get from Sweet Maria's. Drop temperature is between 395-400 degrees which is just before Second Crack on this machine. Each batch completes in about 10 minutes or so.

My standard routine usually has been roasting either 2 or 4 back-to-back batches. After dropping a roasted batch, I set Heat 0/Fan 10 while I prepare the next batch, and during this time, ET drops to about 340 or so, after which I set Heat 100/Fan 10 then charge the drum when ET hits 400. I've found that my best and most consistent roasts occur when the burner is visibly red hot and ET is rising.

Instead, if after the previous roast the ET has dropped down to my routine Charge temperature of 400 but the burner is dark when I charge, I've not had anywhere near as good of a result because of the lag time between hitting the Heat button and that heat being evenly applied to the chamber.

For whatever reason, I completely missed the recommendation from both Hottop and Sweet Marias to allow the unit to cool down to "surface touchable" level between batches because "continuous" roasting was not possible without extreme risk of melting the drive gears. At least 20 minutes cooldown between batches is recommended, but adding an extra hour to a 4 batch day just isn't going to swing it in my life.

Over my last 7-8 roasts, the drum's rotation has gotten significantly stiffer. I first noticed it being harder to manually turn when I was spinning it with finger pressure while looking for burnt beans stuck in the anterior fins. A few roasts later it was extremely sluggish on startup but would come up to speed after about 30-40 seconds then function normally for the roast session.

I followed Hottop USA's online instruction guide and video series as I took thing apart looking for areas of friction or failure. Everything was in order until I got to the motor itself which was quite sluggish when plugged in alone, so I opened it up.

The gears were intact and were coated with dense, black grease. The bearings also were intact, but the front, and especially the rear, motor housing bearings were quite stiff and were coated with what appeared to be roasting oil that had gained entrance to the motor housing through its rear vents.

Prior to mucking with things further, I contacted Hottop USA's service department by email and quickly was advised that the black grease was normal as factory applied but that Hottop USA had no luck servicing motors and that once a motor goes south, it just needs to be replaced. New ones are not chump change at $180 plus shipping, so I figured it was worth me having a go at a cleaning job to see if the problem was there rather than with some electrical failure of the windings.

A quick small shot of degreaser spray via an extension tube was applied to only the stiff front and rear housing bearings, and after a few minutes, several Q Tips were used to rub it around then swab up the excess. A touch of Inox MX-6 food grade bearing grease was applied, and then the bearings spun freely. Since the gears all spun freely on their respective shafts/bearings, I just redistributed the original HT black grease to better coat them so as to not mess with things further but especially just in case there was something magic protection-wise about the original grease.

After reassembly, the motor ran perfectly fine on bench testing, and it's performance was back to normal once the roaster was reassembled.

So the take away point is that my near continuous, multi-batch roasting routine DID NOT do any irreversible damage to my motor, and that even if if it did gunk the motor up and slow it down prematurely, a low level degrease job was all that was necessary to correct the problem.

I understand that this may pertain to only my roaster and YMMV on yours, but I plan to continue with my present near continuous back-to-back roasting routine for now. Don't be afraid to attempt a similar fix on a sluggish motor. My wallet is VERY HAPPY right now!

I've enclosed some pictures. I marked the motor housing with a vertical line prior to disassembly in order to assure proper realignment. Watch out for the thin spacer on the armature and especially the two tiny ones encased in grease on the big first drive gear spindle. You will lose them, at least for awhile, if you aren't careful- ask me how I know!

The bearing in the rear of the motor housing has a 120 Volt sticker covering it and is there to keep junk out of the bearing. It is EXTREMELY thin and probably is easy to tear. To avoid poking a hole in it, I first held the motor housing firmly to my bench while scrubbing inside the bearing with the QTip. There was enough play in the sticker to allow me to carefully and lightly get under it with a final clean QTip once I held the motor off the bench.


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#2: Post by baldheadracing »


FWIW, if you ever plan on regularly doing many back-to-back roasts, then you may want to consider ciel-007's RAF - reverse airflow mod: ... ad_id=3236

As an aside, here are the full set of mods that he did to his Hottop, although some of these do not apply to the 2K+:
Part 1 ... ad_id=2759
Part 2 ... ad_id=2785
Part 3 ... ad_id=2815
Part 4 ... ad_id=2978
Part 5 ... ad_id=2999
-"Good quality brings happiness as you use it" - Nobuho Miya, Kamasada


#3: Post by Coffeevalley »

Thanks for the guide! Also +1 for the RAF mod. It made a noticeable difference for me. I liked my roasts before the mod but the RAF really reduced the smoky flavours.

I have a 5 year-old b2k Hottop and I couldn't get the other mod that shorts the thermocouple to trick the machine into going straight into preheat mode so I couldn't do the back to back roasts I was hoping to and I used that as an excuse to buy a new roaster.