It won't self-convert any more, I wouldn't think. Also be careful of getting the malt into the "Harsh Zone", the range of color where the malt tastes harsh and ashy. But it is an interesting experiment: Taste it afterward and you may have to store it for a while to mellow.
If you only "kill" part of it, no problem. Add back some light base malt (Pilsner, 2-row, etc.) to recover the diastatic power. If you use 2-row or 6-row, add back the amount you roast - both are capable of converting their weight plus an equal amount of other malts. And for roasted malt, you're not doing a lot of converting, there's not much starch left in them. That's why you can steep them for use with extract.
The Recipe Calculator would beg to differ.
There's 32-34 PPG in dark roasted malts. It's less than the 38 or so for base malts, but starches present in the malt didn't go anywhere when they were heated and they definitely add to the fermentable sugars.There's not much difference in Carafa and Chocolate roasts. If the number is similar, you'll get very similar results. I tend to keep regional malts together in recipes, using Carafa malts in German beers and Chocolate, etc in English beers but it's just a preference and won't make much impact on the final product if you mix rather than match.
I’d like to keep them together too. I use so little of those roasted/specialty malts that it was easy to just buy a pound of chocolate since I make more English beers.The Recipe Calculator would beg to differ.
There's not much difference in Carafa and Chocolate roasts. If the number is similar, you'll get very similar results. I tend to keep regional malts together in recipes, using Carafa malts in German beers and Chocolate, etc in English beers but it's just a preference and won't make much impact on the final product if you mix rather than match.
I didn't say there was no extract in them, just not a lot of starch! You can get quite a bit of extract out of roasted malts through steeping, this is from Palmer's "How to Brew" site:The Recipe Calculator would beg to differ.
There's not much difference in Carafa and Chocolate roasts. If the number is similar, you'll get very similar results. I tend to keep regional malts together in recipes, using Carafa malts in German beers and Chocolate, etc in English beers but it's just a preference and won't make much impact on the final product if you mix rather than match.
It would have been easier to handle whole.... You're increasing the surface area exposed to heat so it may roast to the point you want quicker. Keep an eye on it and you should be fine.
I think you definitely do need extra diastatic power to convert (depending on depth of roasting) because the heat involved in roasting will surely denature the enzymes, (though I suspect that exact process is different than the activation and denaturing that takes place in the presence of water). I'm just contending that if there was starch in place before roasting, most of it should still be in place after roasting and would be available for conversion by enzymes provided by other malts.
