HotTop - top filter?

#1: Post by **Rallendk** » May 3rd, 2013, 5:06 pm

Hey there.

I am picking up an old HotTop tomorrow, as an upgrade from my current Café Gene roaster.

I have been reading a bit around about the HotTop, and found out that it features 2 filters - a top filter and a back filter. I am planning to replace the back filter with a 120mm aluminum fan gitter is explained in this guide:
http://www.espressomyespresso.com/Hotto ... ilter.html

Now I am wondering though, what should I do with the top filter? Can I just leave it as it is? Clean it once in a while (how?), or replace it with something whole different?

Any other comments about recommended mods or anything else about the hottop would be much appreciated.

Thanks already!

#2: Post by **Randy G.** » May 3rd, 2013, 5:21 pm

The material in the top filter, particularly used ones, is quite fragile. Unless it is damaged or particularly filthy, leave it. You can inspect it by removing the two little screws and taking it out as a unit. Look underneath as the filter material is exposed there. You can replace it with a cut piece of the black stuff from a used rear filter if need be.

#3: Post by **JohnB.** » May 3rd, 2013, 6:09 pm

Another alternative is to remove the filter material & replace it with insulation to hold in heat. There are plenty of gaps around the chaff tray & lower front to allow air flow when the fan is running.

May 3rd, 2013, 7:39 pm

I've never heard of anyone doing this but I am intrigued. Is this how you run your hottop? If so does it have any affect on your profiles?

#5: Post by **JohnB.** » May 3rd, 2013, 9:09 pm

I've been running my Hottop with the front filter blocked off for over a year now. Since the heat isn't rising up & out of the drum area as fast it should help some when roasting larger batches or when you are trying to push the roast.

#6: Post by **Nik** » May 4th, 2013, 3:37 am

I can vouch that John is 100% right on this one. He gave me this tip a couple years ago and I have roasted hundreds of batches without touching the top filter. I have no problems roasting up to 10 oz batches and achieving a 300F bean temp in 5 minutes or less. I do use a variac and adjust it according to the batch size.

I am still trying to understand how the new, larger Hottop went from $2000 to close to $6000. I was looking forward to the new one as many others were as well.

#7: Post by **rama** » May 4th, 2013, 10:35 am

I'd just inspect it and leave it alone unless its really trashed- it really doesn't seem to serve a purpose.

I insulated my Hottop between the outside walls and the drum roughly 2/3 down all the way to the top, with only a slight gap at the top to allow moisture/smoke another way out. It didn't result in a noticeable change in RoR, but I live in a temperate climate.

#8: Post by **rgrosz** » May 12th, 2013, 1:34 pm

Nik wrote:I can vouch that John is 100% right on this one. He gave me this tip a couple years ago and I have roasted hundreds of batches without touching the top filter. I have no problems roasting up to 10 oz batches and achieving a 300F bean temp in 5 minutes or less. I do use a variac and adjust it according to the batch size.

After about 50 roasts on my Hottop, the top filter had shrunk to about half its original size. This resulted in more heat loss, and extended my roast times by 1-2 minutes. I noticed an immediate improvement after I replaced it with a new filter from SM.

May 12th, 2013, 6:54 pm

I have never checked mine since it was new and there has been quite a few hundred roasts through it. I don't think there is any heat loss. Yesterday I roasted my first 10 oz batch and hit the targeted 300F in 5 minutes and first crack a bit before 9 minutes. I may try 10.5 oz next...maybe a peaberry bean!

#10: Post by **rgrosz** » July 6th, 2013, 8:31 am

rgrosz wrote:After about 50 roasts on my Hottop, the top filter had shrunk to about half its original size. This resulted in more heat loss, and extended my roast times by 1-2 minutes. I noticed an immediate improvement after I replaced it with a new filter from SM.

I wanted to follow up with my results after replacing both my rear and top filters. I keep the rear filter in good shape, so I attribute almost ALL of the change to replacing the top filter.

My roasts have gotten SO fast I had to adjust all my profiles. Here are two roasts of some Ethiopia Sidamo from Theta Ridge. I did not make any change to the profile for this bean. Normally I would roast to FC + 2:30, but I had to eject the beans at FC + 2:00.

NOTE
The temperature shown is from the front display panel of my Hottop.
My installed thermocouples do not work #TC-FAIL

Prior roast - 265g - 01/05/2013 - old filters

	DISPLAY     								Rate of rise
TIME	TEMP	FAN	HEAT	Milestone     per minute
 0:00	215	 0%	100%   		drop 265g beans into roaster
 8:35	320	25%	100%		
10:30	350	50%	80%		
12:50	381	50%	70%	First crack	
13:20	386	75%	40%	1C + :30	
13:50	390	75%	30%	1C + 1:00		9
14:20	393	75%	30%	1C + 1:30		7
14:50	397	50%	30%	1C + 2:00		7
15:20	399	50% EJECT	1C + 2:30		8

Recent roast - 265g - 06/08/2013 - new filters

	DISPLAY     								Rate of rise
TIME	TEMP	FAN	HEAT	Milestone     per minute
 0:00	215	 0%	100%   		drop 265g beans into roaster
 8:05	320	25%	100%		
 9:55	350	50%	80%		
11:55	383	50%	70%	First crack	
12:25	388	75%	30%	1C + :30	
12:55	395	25%	30%	1C + 1:00		12
13:25	399	25%	30%	1C + 1:30		11
13:55	406	25% EJECT	1C + 2:00		11