It's an interesting topic Marc - especially temps. Whilst my experiences are not directly with the BDB, I can relate to what I have noticed on other brand equipment that offers direct PID controls of the brew temp. I may have mentioned this in another post, but I'm tired and can't be bothered searching.......sorry. A few years ago, everyone was heading up in temps - the movement was led by the specialty cafes using LM's and dialing up a higher temp (sitting around 93 and 94). It was thought at that time the higher temps were addressing sourness and delivering sweeter shots. Most people had assumed their machines were running around 92......in fact very few actually took the effort to properly measure using approved methods. Just like fashion, there was very little science behind it.......just a bit too much hype and mindset. Some of this theory about higher temps may have been true, but I have a strong belief it comes down to more about the profile used to roast the bean and matching that to an extraction temp. It could have been a style of roasting at that particular time which worked better with the beans they were using at higher temps. Who really knows...... Of course, we also know there are some beans that prefer lower temps. I've found Colombians, Brazils and many South Americans enjoy a lower temp. I've run tests at 89 on my units and achieved some very tasty shots - straight or with milk. Having experimented myself a lot over the last 3 years, I've settled on 93 as the best setting for my machines. Of course, when I'm working it the temp drops to 92, so perhaps somewhere between 92 and 93 is perhaps the best spot. I have tried to establish a link between the origin, acid, density of a bean and it's subsequent preferred temp, As an example, I had long thought low acid coffees work better at low temps (some people would argue that it's sour) and the acids work better at high temps, but then as always, the logic busting shot would rear it's ugly head and blow my theory to bits. Ultimately, the only thing I learned was to stop playing with temps............took me a long time to finally accept that lesson. I'm a big believer in pre-infusion - whether it's mechanical or electronic. We play around with this setting on some of the more advanced super-autos with good results and when you consider what happens with levers........it's perhaps one of those features that may actually be truly beneficial. Marc - enjoy the experimentation, if anything it will broaden your understanding.
