[homoeccentricus]

I got myself a Gene Cafe roaster for Xmas, and was wondering whether it is possible to roast decent quality darker malts in it. Anyone has done this without setting the house on fire or blowing up the roaster? Does the malt need to be soaked in water first? What would be the roasting profile?

[morticaixavier]

I've not done it but I can't imagine why it wouldn't work. Some of the small craft maltsters that are popping up now use the small commercial coffee roasters as malt roasters.

It happens fast with the little grains though so keep your eye on them.

[reverseapachemaster]

I don't think the process would be too different but due to the difference in size between grain and bean the grain will roast faster. It will make a difference between roasting green grain and pre-malted or dried grain. If you can source green grain to use then you'll have to go through a drying stage before roasting, just like you do with coffee.

You need to soak the grain to make crystal malt but I wouldn't want to get that much moisture inside a coffee roaster. Seems dangerous with an electric heating element not designed for liquid use. I'm also not sure you could keep the grain at saccharification temperatures long enough to thoroughly convert the starches with a home roaster.

[homoeccentricus]

To play it safe, let's assume I start with pre-malted grain. 

[morticaixavier]

looking at pictures on line of that roaster I can see two possible issues:

first, the paddle that keeps the beans moving appears to be perforated. are those holes bigger than a barley kernel? If yes it's probably not a deal breaker because it will still move things around just fine.

second, the vent at the bottom of the cylinder, are those slots bigger than a barley kernel? if so I would be afraid to put grain in there for fear it would fall through into the heating element and catch fire. you can probably test both things by removing the cylinder and putting some grain in and shaking it around a lot.

[homoeccentricus]

To play it safe, let's assume this is a purely theoretical discussion. 
But I'll have a look over the weekend as I have to roast coffee anyway.

[MDixon]

I personally think it is going to be too hot. Roasted Barley does get up to 500F, but roast too much and you get fire. Chocolate is 300-400F or so and with coffee at 401F you are just hitting first crack. You aren't going to make crystal malt because that doesn't come from finished malt, it comes from allowing the kernel to sit at saccharification temps and then it is dried and kilned. So about all you can make is Chocolate or Black Patent and I wouldn't bother since your roaster is going to heat too fast.

Some quick links on malt:
http://byo.com/hops/item/1108-malting-your-own-techniques
http://www.tucsonhomebrewclub.com/index.php?option=com_content&view=article&id=42:more-than-you-want-to-know-about-roasted-grain-in-20-minutes-or-less-&catid=5:articles&Itemid=33

The best chart for coffee is George Steinert's Degree of Roast/Temperature chart. I use it every time I roast and simply roast to temp instead of visual. Almost at the bottom of the page.
 http://www.sweetmarias.com/library/content/using-sight-determine-degree-roast

[leejoreilly]

While I can see the attraction of doing it for the sake of doing it, I'm not so sure of it's practical value. I would think it would be difficult to accurately rate the SRM color of the roasted malt (for accurate brewing records), or to duplicate that color in subsequent batches. But it still might be fun to just try.