Hey there guys.

I'm roasting using a Hottop 2k+ , and have been actively roasting/testing/learning using 100 gram batches (recommended batch size is 250g). I already know the same roast profile that I like fo 100 grams won't be 100% portable to a 250 gram batch size. I've tested that numerous times to know timing, temps, etc, all don't relate.

Is there some type of known mathmatical and tested formula for bigger ratios that roasters learn through trial and error that's passed around?

Example: (below numbers are not to be taken seriously..)

If charge temp for 100 grams is 260 ET, for 250 grams charge in at 300 ET
If heat is dropped by 20 degrees after FC for 100 grams, decrease it only 10 degrees for 250 grams.

etc etc.

Any hottop 2k+ users notice a ratio or set of rules that work consistently for larger batches?

I've settled on 175 grams as the "sweet spot" with my Hottop. They "say" 250g as they sell it as a half pound roaster but my personal experience is that my roasts are more consistent using 175g or less when the weather is colder but as with anything YMMV

As far as porting profiles, I've found that each bean and even each new batch of the same bean will roast differently. I try to stick with purchasing a minimum of 10# of any given product then get it dialed in @175g and don't vary from what provides the best results that I am after.

I've had some heated discussions with people about home coffee roasting being art, craft, science, and even voodoo. Too many people want to make it like toasting bread (stick it in for xx seconds each time). Trust me.... it isn't something you can automate in small batches as there are way too many variables outside of the bean and roaster, such as the ambient temp, voltage fluctuation, humidity, altitude, etc. You will be surprised how much little things can affect your outcome. Now for large batch roasters (5 kilo and up), you don't have the issues of a thin walled home roaster as you are working with a massive amount of steel running at a consistent temperature which makes the little things that will drive you nuts when using a small home roaster of no consequence.

Home roasting is a hobby and should be treated as something that is done solely for the enjoyment of the task.

I know this does not answer your question but I figured to toss something out to you since no one else has responded to your topic.

Thanks Turtle.
I appreciate all the info.
I've been working with 100 gram roasts, (saving on some beans before settling down on bigger batches). And thanks, I suspected the best would be just shy of 200 grams.

Curious to know as I've been working with this just recently.
I'm actually charging at the desired temperature using a 70-80% power level, so if I need to ramp up, I can blast at full power. If I need to scale down, I can do so as well. It's been giving me a longer roast time and modulating the flavor by just sticking with a power level of around 70-80 at start and throughout the roast. Something that came new to me as I was using 100% power for thermal momentum. Curious to know if you're also using less heat?

With the hottop I use 100% power and control time/temp/ROR with the fan. I have replaced the paper filter with a mesh computer screen that is almost full flow so a little fan for me is like a LOT of fan used to be. I roast outside so I do not have the need for the paper smoke filter. I found that using nothing was not good as the roaster needs some fan restriction, just not as much as the stock set up gives (not for me anyway).

I have the stock/original burner in mine and I found it inadequate so only run it wide open, controlling the roast by removing hot air from the roasting chamber. Control is much faster this way as the electric element takes a little too much time to adjust up and down for me.

I should also say that I control fan/burner with artisan which gives me more steps than the stock 4 step on-board fan/burner controller in my stock B model panel.

I've been roasting 200 gram batches in my B-2k for about a year now. Prior to that I experimented with batches from 175 to 227 grams, ultimately settling right in the middle. I've also had thermocouple probes installed through the back wall for a little longer than that.

I consider what I aim for to be more "production-style" roasts (around 11-13 minutes), rather than the much faster (7-9 minute) "sample-style" roasts those using smaller batches often talk about. However, the balance for me in choosing a batch size, was finding an amount of coffee I could get to first crack as quickly as I want without tasting any scorching. At 227g (half a pound) I was having difficult getting to this point sometimes even by 10 minutes, depending on the coffee.

My standard profile right now involves a charge temp around 400F with heat at 80%, increasing to 100% at 1:30, then slowly backing off heat from yellow and on. Total time and phase lengths vary depending on the coffee and what I'm aiming to do with it. For most coffees, I'll start with the fan at 50%, and increase to 75% at yellow.

My hottop has been through a few changes (reverse airflow mod, cooling cycle bypass, added thermocouples etc) so this may not be a good example also this is a bit of a generalization as it does vary with beans. Anyways I charge at between 320F for DP coffees and 340F for washed high grown. First batch is 230gr subsequent batches are 260gr. Heat at 100% and no fan. Stopper for reverse airflow out at 280F and in at 320F. Fan at 25% at 320F to remove some moisture. Heat down to 80% 30sec before first crack, air up to 40% at the same time. Heat off at FCe and air up to 50%. Drop times vary with the bean. This gives me a 9min to 10minute FC, a steadily declining ROR and about a 2 minute FC to FCe.

Cheers
Ian

Would you guys be charging at your stated temperatures at ET, not BT? I can't imagine you guys are charging 400 BT .

Some clarification would be nice Thanks for the backdrop information!

ET and BT should be about the same an an empty drum.
Cheers
Ian

coffeetempo wrote:Would you guys be charging at your stated temperatures at ET, not BT? I can't imagine you guys are charging 400 BT .

Some clarification would be nice Thanks for the backdrop information!

The below is true. In a sufficiently preheated, empty roaster, my ET and BT read within 5 degrees of each other. When different, I charge based on the ET probe, as (probably due to placement, being more directly in the path of airflow) this has lead me to more consistent results.

woodchuck wrote:ET and BT should be about the same an an empty drum.

Hi Everybody,

I am new to this forum. Just bought HT 2K+ recently. Happy that I am not alone using HT as there are just too many Huky communities. Glad you guys are sharing experience and I enjoy reading this. I will provide my little knowledge for sharing

I started with our single origin bean (nothing else) which I think helped me in reducing the bean variable factors. I also agreed with what turtle wrote
I started with 150gram (charging at BT 170F) and it was good starting size for me. I found the right profile for me after many attempts

When I moved to 250g, I was doing it in the blind as I like the 150g profile and wanted to repeat that it was tough initially but changing the charge BT (200F) helps to make it close to the profile with other adjustment like heat level (as batch size is bigger) during the roasting. I tested the coffee with many friends (small circle of non connected) and most finds the coffee of 150g and 250g tasted same.

Next I have the biggest question since day one after reading many blogs and forum and I hope someone can share with me. My BT never caught to ET in all roasting. I have seen other with chart/diagram showing BT crossing ET in the middle or end of roasting. My question is must BT cross or meet ET during the roasting?

Thank you for reading and hope to hear your comment.

Regards
desmond