I've been roasting two to three pounds of single origin beans or blends at a time. I'm using a 12kg unit from US Roasters Corp.
I place a sticker w/ blend information on or in each container of the pre-blended roasts the day before roasting and seal the container to allow the beans to reach the same moisture content. Then I put the recipe information in a log book w/ each example given a number. The name and numbers are then placed on the individual bags in which I place the pre-roast blends or add the components of those blended post roast. (Heart and Soul #1, Heart and Soul #2, etc.) I then grind a portion of each bag and place the grounds in cups sitting in front of the corresponding bag of whole beans. We then sample each variation of a blend and attempt to reach a consensus on the best offering. Those not making the cut are pushed to the back of the counter. Those deemed worthy of further consideration are left up front and revisited as the coffee cools. Eventually one is chosen that stands out through all temp changes. At that point, I take the "winner" and cross reference with the log book to find out the exact recipe/ratio used. If I come up with another recipe idea days later, another blind tasting is done with the first winner going up against the prospective recipes in another blind taste test.
Roasting bog batches on this roaster is pretty easy. And I really haven't had a problem getting consistent results with the small batches either. I start at a certain temp, activate a stop watch when the beans are added to the barrel. The record the temp drop in the drum and then use a chart to get on track with time/temps. With this roaster, the goal is to complete a roast in 15 minutes regardless of temp reached. (So a 420* roast takes the same amount of time as a 450* roast.) I have marks I want to hit as far as time/temps go with each roast level. If I'm behind, I add gas to speed up the process until I'm on track. if I'm ahead of the desired rate, I slow down the roast by letting up on the gas. There is a temp indicator for the beans and another for air temps in the barrel. Keeping the air temps slightly above the bean temps makes for a slower roast. Raising the air temps a considerable amount above the bean temps raises the bean temp quicker. When the air temp in the barrel is lower than the bean temp, the roasting process stalls out.
So far, I've managed to get almost all of my roasting efforts to the desired roasting temps within ten or fifteen seconds of 15 minutes. One effort did take only 13.5 minutes and another went about 16 minutes. But out of 30 or so efforts so far, the vast majority came out of the drum right at 15 minutes.
I have given away a lot of coffee this last few weeks to friends, family, neighbors and folks coming to the shop to see if we are open yet. The first bit went out in zip lock baggies. Now I get them in our kraft paper bags w/ labels.
We are looking to poen for business on Monday.
lw