another_jim wrote:If the vacuum held and the roast was undeveloped, the frozen beans may be a red herring. Check the roaster: sensors, airflow, and heat. Sounds like you may not actually be using your "perfect profile (tm)."

Wish this was the case (wait, maybe I shouldn't!). Nope, roasting setup is all good.

Here's where we are so far:
0. All 3 bags held vacuum, thawing was done slowly (day or 2) at room temp before opening a bag.
1. A much muted 1st crack (compared to never-frozen batch on the same profile).
2. Result had no aromas and was sour even when pulled at very high temps.
3. Extra rest makes it worse.

H E L P ! !

In my experience of profile roasting, what your describing usually happens when I use too low of an ET. I don't know the scientific rational, but if I raise my target ET by just 10 degrees F after drying it usually solves the problem. You may need to drop the ET back down a bit after or just before 1C depending on your desired roast level/finishing time. I have experienced this mainly with DP Ethiopians where the berry just doesn't want to come out unless I hit that higher temperature. Rather it is replaced with either a flat or slightly astringent quality that won't go away even with an extra minute at the lower temperature.

Dave, you might be onto something! Your advice sounds so right, I'll just go for it on my next roast.

BTW, I have a hunch you'll post some great stuff on this forum, welcome to H-B!

I joked in a previous thread that some of my expensive beans look like bricks of cocaine or weed, wrapped up in my freezer. I vac-sealed them, then wrapped them tightly in heavy duty aluminum foil, to really ward off freezer burn/moisture loss. Then the whole lot of them got placed in a large 2 gallon zip top bag.

At least the roasted coffee doesn't require this much work. I am happy with pint size mason jars, filled to the top and popped in the freezer.

coffee.me wrote:Dave, you might be onto something! Your advice sounds so right, I'll just go for it on my next roast.

BTW, I have a hunch you'll post some great stuff on this forum, welcome to H-B!

Thanks Max! I look forward to your results.

This is getting quite interesting! I roasted one more batch and...

Dave's ET comment was spot on BUT that's not all! Those frozen beans somehow inhibit ET from ascending as fast as usual from my Hottop! It is like they absorb heat faster than never-frozen beans, making it easier to increase BT than ET...and no, my probes aren't switched.

Roast details: I did one more roast following Dave's advice, I cranked up the element to maximum and it glowed like fireworks but ET wasn't increasing as fast as with the never-frozen batches but BT did! I got better ET's than earlier batches and it resulted in a better roast overall; not as good as the never-frozen though. I know it's not the HT's element because it shined like a star, so it got to be the frozen beans.

For my next batch, I'll have to rework the whole profile to compensate for this freezer effect.

TomC wrote: I vac-sealed them, then wrapped them tightly in heavy duty aluminum foil, to really ward off freezer burn/moisture loss. Then the whole lot of them got placed in a large 2 gallon zip top bag.

At least the roasted coffee doesn't require this much work. I am happy with pint size mason jars, filled to the top and popped in the freezer.

That is serious over kill if you are using good good quality vac bag stock. I vac bag with the Foodsaver using their rolls & have seen no sign of freezer burn/moisture loss. Some of my greens have been in the deep freeze for 2.5 years at this point. If the bags are holding the vacuum air can't get in & moisture can't get out.

another_jim wrote:If the vacuum held and the roast was undeveloped, the frozen beans may be a red herring. Check the roaster: sensors, airflow, and heat. Sounds like you may not actually be using your "perfect profile (tm)."

+1 - sounds like a power issue.

Take the back off the HT and have a look at connections. Look for anything discolored.
Clean out any accumulated chaffe

Remember that power varies as the square of the voltage change. If your utility drops the voltage to compensate for summer load, you could be a mile off the profile.

BTW, is EU Etats-Unis / 110v or European Union 220-240v

cafeIKE wrote:+1 - sounds like a power issue.

Ian, in case you missed my last post on this thread (the 2nd one up from yours, here), I'll summarize: BT stayed close enough to the path of never-frozen, it was ET, alone, that couldn't match....and my thermometry is OK.

How can that be explained by power issues? If anything, BT usually follows ET, ET is faster to react to a power increase while BT is more sensitive to a power reduction. But if there's a good explanation linking power to this matter, I'll be very eager to hear it.

Did one more roast and also measured voltage just to be sure

Voltage is fine, exactly what it has always been.

This latest roast demonstrates the ET issue very clearly, the profile was changed to go to max heat earlier than ever before. Check this out:

• With never-frozen batches, ET-BT delta was 55F a minute before 1st...and high heat was only used for a shorter period than on the frozen batches.
• With this latest frozen batch, which was the most aggressive so far, ET-BT delta barely touches 40F a minute before 1st...and max heat was used for a longer period than on the never-frozen batches.

What the!!!???