HotTop Insulation for winter roasting

[Tex]

I may do this to my HT this winter. If I do I'll use foil and fiberglass duct insulation . It comes in 12" wide rolls and is easy to work with.

I'd also get the foil-backed tape to seal it.

I'd do some research as to how that insulation will handle high temps. 

Thanks for reminding me peter; maybe I'd better take some readings to make sure? I've used it to insulate boilers to 300°F, so the exterior of the HT should be OK. I also have some melamine insulation that might work.

[peter]

Thanks for reminding me peter; maybe I'd better take some readings to make sure?

Now, Tex...  that's twice in less than a week that you've been agreeable and congenial.  Did you get religion, or what?  If you start treating Susan kindly too, we're going to send the men in the white jackets to come and take you away.

[Tex]

Thanks for reminding me peter; maybe I'd better take some readings to make sure?

Now, Tex...  that's twice in less than a week that you've been agreeable and congenial.  Did you get religion, or what?  If you start treating Susan kindly too, we're going to send the men in the white jackets to come and take you away.

Thanks for reminding me yet again peter! I'll take corrective action immediately! :argue: Me be nice to Susan after all the mean things she's said about you? Never, not even if they are true!

[grinderz]

Thanks for reminding me peter; maybe I'd better take some readings to make sure?

Now, Tex...  that's twice in less than a week that you've been agreeable and congenial.  Did you get religion, or what?  If you start treating Susan kindly too, we're going to send the men in the white jackets to come and take you away.

Thanks for reminding me yet again peter! I'll take corrective action immediately! :argue: Me be nice to Susan after all the mean things she's said about you? Never, not even if they are true!

 

[Tex]

Awww..., Isn't that a cute pookah? Hello Harvey, long time no see?

[GC7]

Well I got what I needed to insulate the HotTop and thought I'd report on my progress.  

I'm pleased with the fiberglass paper insulation.  It's easy to work with and cut.  I choose to use some extreme temperature foil tape to maximize the chance this will last if my profiles are good in cooler ambient temperatures. I have a cutout for the top filter to cover it as needed and I can do so for the vents on the side as well.  I do not know how this change in air flow would affect roasts.  I guess we will see as colder weather decends on us and if preliminary results are encouraging as to profiles and heat requirements in different ambient temperatures out on the enclosed porch.

Here are a few photos

[mp]

Nicely done ... let us know how it works "in the field".

 

[GC7]

Here are the results of my first pre-heat test.
Its 55* here on the porch and the voltage with the HotTop heater running is 117.2-118 which is normal for that outlet.
My brew coffee profile uses maximal time (25 min) and temp (428*) and I start the roaster. At the beep when it hits 167* on the HotTop display I reduce heat to 7 and without fan let the ET as shown on my bean temperature probe wait until it shows 350* (+/- 5*) which happens at 21’ 30” on the display when I drop the beans and raise the heater to 8 or 9 to dry beans depending on profile.  With the insulation I really did not know what to expect but possibly to reach 350* sooner.  However, I did not see that happen.  The insulation is also quite hot on the foil as well.  We will see if I need an additional layer with this stuff.  The real test will be when the roasting ambient temperatures go below 40-45* and I do a real roast.

[peter]

Way to go, Einstein.  

I would expect the advantage to your project to be how it roasts in the wind, maybe more than simply holding heat in.

[GC7]

I'm no Einstein but I do greatly admire his humanity and especially his ability to simplify very complicated topics to the point where he could educate everyone about his theories. Great minds and great people have the ability to simplify and I try as best I can to emulate that in what I do. Weak minds and those trying to impress will complicate everything usually because they don't fully understand the topic.

I did my first test roast with the insulation and my preliminary results are very encouraging.  While the time to get the ET to where I wanted o drop the beans did not change using the same program, I did get to first crack significantly sooner even lowering heat after drying (from what I usually use). I did however over-react and lower the heat at first crack more then necessary and stalled the roast for a minute or so at about bean temprature 407* towards the end of first before recovering with more heat added.  I think with some patience playing with the heat, this modification will improve my cold weather roasting.

More detailed data will be forthcoming with my next roasts.

[GC7]

I thought I would report on my cooler temperature roasts with the insulated HotTop.  It’s 45* out on the enclosed porch and no golf this weekend so I have time to roast.  The voltages are all normal and within 1 degree of standard HotTop use.
My first roast was Organic Mexican Oaxaca HG (my standard 170 gm load with 10 minute time to first crack being standard).  My prewarm up was as expected and reported last time where at 21’ 30” on the HotTop display I dropped the beans at ET 340*. I watched the bean temperature thermocouple carefully using my typical profile.  Turn temperature was fine as was drying period but I needed to lower the heat after drying to prevent too steep a ramp and too fast onset to first crack.  It seems that the insulation does indeed preserve heat even in these cooler ambient temperatures. I’d estimate that I could have reached first crack a good minute sooner without adding any power to the heat coils had I wanted to do so.  Slowing the roast and keeping about a 10 degree per minute rise in temperatures to complete the roast is a bit tricky but certainly doable by paying attention to the heat levels. 
To summarize, this insulation modification seems to work well to enable modest heat application to the beans that keeps MET and ET’s within ranges that don’t hurt the beans.  I see no tipping, burning or defects in the roast. I’m very pleased so far.
I did a second roast with Ethiopian Amaro Gayo.  I tried to let it ramp a bit faster as it’s a harder bean and I wanted a brighter flavor. I got it to first crack at 9 ½ minutes and was able to slow it down to my 425* finish.  I had to watch the ET getting a bit higher than the first roast.  Still no burning but one needs to watch the heat carefully.
The best part – TASTING- to follow.

[GC7]

I’ve had some time to do quite a few roasts with ambient temperatures into the thirties and with a bit of wind blowing through the screened porch where the roaster lives. These types of conditions would have required altering the heat input and profiles of my uninsulated hottop. I was never really very happy with my winter roasts.
I must say that I continue to be pleased with this modification. The effects of the insulation as suggested previously are I believe mostly in holding heat within the drum.  This plays less of a role in preheating the roaster and in drying phase for the first few minutes than the ramp up to first crack and coasting to the finish which are really enhanced and the heat retention is noticeable.  You need to be on your toes with the heat input and watching environmental temperatures.  I am now dropping beans at about 330* to 340* and getting turn temperatures of 175*-180* at 80 sec. after dropping the beans.  I manipulate the heat to arrive at first crack from 9 ½ minutes to 10 ½ minutes (I could easily go faster – could not do that easily without the insulation even in warmer ambient temperatures). I am now able to use very low (3-5) heat input to finish most roasts 3-5 minutes after first crack depending on if the beans are for brew or espresso and how dark I want to take it.
Tasting is really the final examination for the modification and I can honestly say that my roasts have never been better.  Brewed coffee has the zip and acidity I’ve expected but sometimes didn’t achieve in the past and espresso retains the expected properties of the bean or blend. I’d recommend trying this if you are stuck roasting with a hottop in a cold garage or porch.

[staylor]

Good reminder, thx. I'm gonna have to get on this one. We had nearly 10 days of -30 Celsius and I couldn't roast, it was annoying. Eventually it got up to zero and I blasted off 3.5lbs for myself and neighbor.

I'm gonna head over to Home Depot in the next few days to see if I can come up with something close to your brilliance.

[GC7]

Sean

I purchased the tape at Home Depot.  They have lots of thicker insulation there too but nothing like the thin stuff I purcheased. In your climate perhaps the thicker stuff would be more suitable.  If you want to try the material I bought I would be happy to put a couple of feet in an envelope and send it regular mail.

At -30* C I would not be thinking about my roaster.  I'd be keeping my butt warm next to a fireplace praying for spring!

[John F]

At what temps are you guys finding problems start when roasting with the HT and at what point is it a serious problem?