Originally Posted by afr0byte
Do you have proof of that somewhere? The crystal thread I saw from Nilo did show a marked difference in attenuation for, for example, Crystal 120. Perhaps I'm not remembering correctly.
Thanks for brining this up. I haven't worked through the numbers in a while. My "it's not going to change your fg by even one point" was off the cuff. I should have said "it hasn't changed my fg by even one point"
I have not preformed these experiments myself, so I'm going off what Nilo posted. I agree that there is a difference, but I don't see it as significant in most cases.
Average attenuation from Nilo's data:
80 % for 2-row
77% for 50% C10, 50% 2-row
70% for 50% C40, 50% 2-row
67% for 50% C120, 50% 2-row
If we assume that the 2-row ferments the same regardless of being mashed with the crystal the 100% crystal fermentability numbers can be derived:
74% for C10
60% for C40
54% for C120
We can use these 100% values to then extrapolated a typical 10% w/w use of crystal the fermentability:
79% for 10% C10
78% for 10% C40
77% for 10% C120.
With the grain bill composed of 10% C120 the fermentability is 3% lower than 100% 2-row. If you started at an OG of 1.060 the FG would be 1.012 if crystal is assumed as equally fermentable to 2-row, and the FG would be 1.014. The difference in ABV is 6.5% vs 6.0%.
Here is Nilo's thread: (post number 108 has the data)http://www.homebrewtalk.com/f128/testing-fermentability-crystal-malt-208361/index11.html