You. Interested in why you are choosing those particular strains; what characteristics you are hoping to create/maintain with them.
That same sort of fruity "tang" has developed in my current batch. My gameplan is to use coarse ground beans in secondary to try and round out the flavor. Will taste daily to make sure the bitterness stays in check.
I'm curious about your yeast choices because outside of the alcohol extaction in secondary technique, i think experimenting outside the box with yeast selection could be key here.
I've yet to find where someone was quite pkeased with their coffeemel; maybe it's time that changed.
I made a coffeemel back in August of 2020 & I thought it was great. This was the recipe I used.
100 grams of very coarsely ground Peet's House blend, dark roast coffee, cold brewed in a BIAB grain bag, 3 quarts of Poland Springs spring water for 24 hrs on the counter, covered. Filtered through a coffee filter to catch any sediment. (It didn't look like an overly strong batch of coffee, but, the flavor is intense without being too strong.)
3 1/2 lbs London Buzz Apiary Wildflower honey,
1/2 packet of 71B yeast, rehydrated for 1 hr beforehand in Poland Springs spring water,
Poland Springs spring water to 1 gallon.
This was before I joined this group & knew ANYTHING about SNA's, pH levels, or yeast happiness. Since making this, I have pretty much switched to BOMM protocols for all my meads.
This finished sweet, 1.030....more of a dessert mead than the semi-sweet I was hoping for. Since making this one, (& many more), I have gotten better @ calculating my sugars. Next time it will be 3 lbs vs. 3 1/2 lbs. I thought I would need the extra 1/2 pound of honey to counter any bitterness, but, that was not the case @ all. There was no bitterness to the cold brew & even though it finished sweet, it was still very pleasant to drink & the coffee notes weren't burped out in primary. I may try my next coffeemel with 1388 & see what kind of BOMM it produces.
I will also try the method of making a traditional & adding a coffee infused vodka solution as suggested by
@CKuhns & others to see which I like best.
As far as the bitterness goes, in my experience, bitterness seems to be extracted from the beans much more by HOT water vs. cold. Any cold brew I've either bought or made myself has been sweet , not bitter. Not saying anyone else is wrong, that's just what I've experienced.
I hope this helps you.
Happy meading