I have a number of baking recipes that call for instant espresso powder. As I understand it, it's dehydrated espresso, used to intensify chocolate and related flavors. Seems silly to buy it when I have this nice espresso equipment.

I would substitute espresso for it but that upsets the liquid balance in recipes.

This is a long shot, but has anyone tried to dehydrate espresso for baking purposes? Any tips?

If not, I hope someone at least gets a chuckle out of the idea.

Coffee (or any other liquid being powdered) is sprayed into a vacuum chamber under high pressure to atomise the liquid, then high heat evaporates the liquid leaving a powder.

I read in a couple of links to use the grounds:
http://www.finecooking.com/item/5434/in...sso-powder

Method Dave describes sounds more authentic... but wonder if can be replicated at home.

Sivetz's coffee technology contains a long section on instant coffee (properly called 'soluble coffee"), giving precise details on the various ways of making it, interspersed with jeremiads calling down god's wrath on all instant coffee producers.

Instant coffee was discovered in the 1920s in Latin America when it was noticed that if a pot of coffee was allowed to dry out, the resulting solid, when pulverized, made a good tasting, albeit unaromatic brew.

However this powdered coffee, made from a proper 20% solids extraction brew, clumped into hard aggregates, much like brown sugar does, when the caramels absorb moisture. The early answer to this was to add milk powder which gave poeple an instant milky coffee. This was used in the 1930s and 1940s, and was, accoding to Sivetz, the best tasting commercial instant by far.

After the war, the industrial chemists at Nestle came up with a technologically much sweeter solution to the clumping problem. Brew the coffee in giant recirculating perculators, at very high pressures, but correct temperatures, to get the solids extraction up to 50%. The extra 30% is mostly cellulose, an ideal declumper. So now you get two and half times as much instant from a given amount of beans, and it doesn't clump, and you can advertise it as 100% coffee. Marvellous. Sadly, the stuff tastes like crap. But if people can be persuaded to buy it, who cares?

The vacuum spraying Dave describes is one method for economically dehydrating the brewed coffee. Freeze drying is the other method. Since the underlying problem of soluble coffee is the horrid degree of overextraction, there is not much differencee in the taste of regular and freeze dried instant.

So, allowing either home made espresso or home brewed regular coffee to dehydrate at drying temperatures below about 150F will get you much better brew than commercial instant coffee. It will however be more of a coffee cube than a coffee powder.

However, I have no idea if dehydrated home made espresso will taste any different from dehydrated home brewed regular coffee.

Use the liquid espresso as is and decrease the total amount of some other liquid in the recipe, ie, water or milk. i sometimes use instant dark roast coffee but the espresso will contain more complexity that will more that likely be lost in the process of drying.