I have been roasting on and off for a number of years now, but this past summer I purchased a Boehmer 1600 and I have been roasting roughly a pound a week with it since. Last week I did my roast as usual in the garage but it was much colder than normal, about 40F in the garage with the door closed.

My typical routine is to get everything in the garage setup and then take everything from inside the house out to the garage. I do a 2min warm up of the machine and then typically will roast on 1lb, P2 D with the max time preadded to the program.

At this point I roast by smell, sight and sound, stopping the roast at some point after 1C but usually before 2C unless I am wanting a particularly darker roast.

Here is the strange thing that happened though, my last roast had to have gone well past Vienna and it never got to 2C, it barely even got into 1C. Once I started to hear 1C the program was finished and it clicked into the cooling phase. Sure the 1C continued for a bit as it coasted on while cooling but I never heard a 2C at any point. Once the cooling phase kicked in that is when I really started to smell the over roasted coffee. I turned on the light in the unit and sure enough they where way over roasted.

So the question I have is what are some of the effects of roasting in colder weather? I have never seen anything like this before, but I will say the lowest temps in the garage per my logs have been around 50F. I realize that I made a huge mistake by only listening and smelling the progress of this batch and not paying enough attention to the color of the beans, but it just seemed odd that they got to Vienna without ever getting to 1C.

Now maybe because the garage was so cold the bean had a much softer 1C than I was used to? I have roasted this bean type many times and in the past 1C has always been very pronounced but not this time.

Thanks,
-Eric

I want to confirm this, but, I have been making so many changes to my homemade drum, it's not fair to blame the beans or the weather yet.

I think successful roast profiles depend on a brief drying phases followed by a quick ramp up to pop the moisture from inside the beans. So... is it possible your Behmor couldn't deliver the needed leap in power to ramp up to 1C quickly? This could be due not only to the cold but also to electricity fluctuations causes by heavier usage in the winter (we have electric heat in our condo building). You didn't mention whether the roast took longer than usual or whether you measured any temperature.

I thought roasts were a bit different when roasting outdoors, but I was just starting to get to know the Quest M3. When I was roasting in the open carport with associated breezes, I would drape a heavy hand towel over my the roaster. The roaster has a metal skin and a wire frame "safety" cage around the drum.
The towel got only warm like it just came out of the dryer.
It think it helped my roasting temperatures but I sure didn't enjoy it as much.

Now I'm tucked into a slot in the laundry room amid all the clutter...
But I'm warm! My wife tolerates the residual smells.

I vented the roaster to the outside using an old dryer vent that existed before we moved in. There were two when we bought the house and the dryer is hooked up to one on the opposite wall. I really lucked out.

Wow!, is this space cluttered; bikes, junk, gardening stuff, coffee roaster
Anyone want to buy a bike? I've got too many.

I think the best advice given to 1600 roasters is adjust batch size. Use a batch size that allows you to hit all the roasting milestones at preferred times. This timing could be argued, but if a roast can not hit first crack by around 9 minutes, the batch size should be decreased. I'm not sure if Behmors benefit from a longer preheating, but I would give that a try as well.

Simply put, the weather is a variable that affects the roast. Many outdoor home roasters will go as far as to covering their roaster with a big box. This keeps the roaster's surrounding environment hot and eliminates wind effect.

Another culprit of roasting in colder than normal environments is overcompensating heat settings. A roaster might crank the heat to keep roast times the same and wind up burning through the roast.

Of coarse, none of this could be the problem.

How old or dried out is the coffee? Old coffees could be the main issue.

I hear the Behmor is a slow roaster, presumably if you don't go with smaller batch sizes, so I'm sure the cold isn't helping.

When I started out roasting with a popcorn popper, I would have to put a cardboard box over it in winter (even here in the bay area) as Jim advised. It does the trick, but makes it hard to hear the cracks.

Also check your voltage if you haven't already. Swapping a typical extension cord with a shorter heavy duty appliance extension cord gained me nearly 2V, which is quite noticeable in how fast you can roast on a Hottop.