Shouldn't be a problem at all, as long as it's not boiling.
I'd more be worried about the quality of his cordyceps, assumming it's sins is, and not militarious. Much harder to get the conditions right for growing them, lots of fakes out there, and the real deal goes for big money. More than gold supposedly.
I get my Cordyceps Militaris from Mushroom Shenandoah on Ebay. Superman herbs/Lost Empire also carry quality Militaris, but much pricier. Both are a 10:1 extract.