"Burning" the coffee

[kingseven]

Lots of people talk about burning the coffee when you use boiling water to extract it. Just to clarify for me:

You aren't actually burning it - you are merely able to extract certain unpleasant flavour characteristics with hotter water. Coffee has already been subjected to much much higher temperatures and its surely pretty stable around the 100 degree mark?

With americanos I have always put the water into the cup first and then brewed the espresso. I used to be of the opinion that the boiling water was bad for the espresso and it should be left to cool off a little before the espresso is brewed on top of it. Aside from the advantage of retaining a better crema, there shouldn't be any flavour differences should there? All the flavours have been extracted and the boiling water is no where near the ground coffee so can't extract any more bad ones. I suppose the only question is - will the boiling water alter the chemicals already extracted producing a different tasting brew?

(hope that made sense)

[phil]

My experience contradicts this assertion re Americanos. I found that putting the hot water on to the espresso destroyed the flavours. My belief is that this happens because the boiling water drives off or destroys volatile flavour compounds, mainly lipids.

When you put the water into the cup first it loses heat to the cup and otherwise has time to cool.

Peter James demonstrated the truth of this to me. Prior to meeting him I'd never made a good americano. Then he made one for me and I thought "wow, what a difference".

Personally I don't make many americanos, but at least it's nice to know how!

[kingseven]

So you reckon that there is noticeable flavour difference. I've always done water first, espresso second - its how I was trained - but I don't really drink Americanos so all I could see was the visual difference with the crema lasting longer. Plus I suppose the crema would help trap heat and volatiles. I don't know how boiling water would affect the lipids but it is interesting!

[robbie]

I am a bit confused as I just use the brew water to make an Americano ... is this wrong? I thought as it was the same temp as the espresso extraction I should be ok. After extracting the espresso I remove the portafilter and use the brewing water to complete a 7oz cup. Why use boling water? I usually only make one or two cups at a time. Tastes good too.
Robbie

[kingseven]

Brewing water is still full of old oils and stuff immediately after the extraction, so it won't taste as good as fresh clean water. Plus water from the brew head must totally destroy your crema?

[robbie]

I just flush until the water looks clean, stop the pour and then use it, only takes a couple of seconds. The head is usually pretty clean when I look at it as I backflush every couple of shots. The crema is not a thick but certainly isn't destroyed, just spread thinner due to the surface area across the top of the cup, then it clings to the side as I drink it. I tried it with the hot water first pouring the espresso into it but it didn't seem to taste so good ... maybe I just have a penchant for old oil

[robbie]

Just tried the hot water in cup then pour espresso technique and I must be doing something wrong as there was hardly any crema compared to the other way. Usually I have really nice patterns from the crema all over the top and the stuff leaves marks all down the cup as I drink it like a pint of Guinness but this time there was little crema and just a thin line left around the top of the cup. Do you make the espresso seperately and then pour it in? I just ran the espresso into the cup of hot water straight from the portafilter.