Visualizing 28 different variables with 28 different colors? ColorBrewer seems to be very useful in selecting a color pallet to represent factors that have up to 12 possible values. 

I have 28.

Is it a horrible idea to represent 28 variables with color? If so, could you suggest an alternative visual indicator? 

Currently I'm using the colors for column side colors in a heatmap shown below. As you can see, the Strain column is not very informative:
This is the best solution I have come up with, I simply found a larger color pallet. The largest I could find was:

http://bl.ocks.org/aaizemberg/78bd3dade9593896a59d

So I merged d3 catagory 20 with the first few from d3 category20b which was inspired from this heatmap tools heatmap tool's source code: