Okay, here's the recipe: .5 gallons water, 1.5 lbs honey, 1 packet Fleischmann's bread yeast. I fermented for about two weeks (until the bubbles subsided), then did a two week cold crash. I did two weeks for the cold crash because my first batch didn't get all the yeast out after a week. So I just took it off the yeast, and did a little taste, and it's sort of musty on the aftertaste. Don't get me wrong, it's REALLY good, it's just that kind of strange aftertaste. The only way I can describe it is musty. But it came out much better than my last batch overall, with a really full flavor and it's balanced just right for me. It's still dry like the first batch, but it doesn't taste watered down like the first one did.
I have a guess as to why this happened. When I pitched the yeast the water was a little too warm, and it sort of exploded. Within seconds of pitching the yeast it was overflowing foam out the top. That died down after the mixture cooled, but it left some residue in the neck of the bottle that sort of turned this dark caramel color. I'm thinking this is what gave it the musty flavor.
Also has something kind of strange happen with the yeast. After the cold crash, there were two distinct layers of yeast on the bottom, with the top one being darker. I thought it was kind of strange how it layered like that. The only thing I can figure is that the first layer is the yeast that settled during the fermentation, and the top darker layer is the yeast that settled during the cold crash. It was a really abrupt change, with no graduation whatsoever.
Don't get me wrong, I would call this a success for a second batch. The musty aftertaste is very subtle, and if it doesn't go away with aging, then I'll just cover it up with spices. I just wanted to get some advice as to how I might refine it for future reference. This is definitely my go to recipe now though. I love the balance, so I'll keep that proportion of honey to water and maybe try some different yeasts.
That is a lot of yeast for what is basically a half gallon batch. I used a teaspoon of bread yeast in a gallon batch, or about 1/2 what you used in twice as much must. Not that this is the problem, but just worth noting.
I also think you have a procedure problem in that you cold crashed and racked off too soon. I climb on a high horse about needing to take specifics gravity readings, but I have barely enough in a gallon batch to do this, so it might be impossible to do in a 1/2 gallon batch. Any way, I would swirl the mead while it is fermenting at least once a day to help keep the mead in supention. Then let it "soak" in the primary for a couple of weeks so the yeast can clean up after themselves. Then cold crash, rack, let sit again, and bottle. You are rackin it out of the secondary before consuming?
Light Fuse; Get Away
It could be, and probably is related to yeast still in suspension. Bread yeast isn't selected to flocculate rapidly so even with cold crashing out might take quite a while to totally settle out.
In the future, I would use a heady intend for alcoholic fermentation. The classic easy to use winemaking stains are 71B or K1V. I would avoid EC-1118 since it can blow off delicate automatics. I would avoid D-47 because if it ferments above about 66°F it makes a ton of fusels. A pitch rate of 2g/gal is sufficient, but a lot of mazers use up to 5g/gal. Learn to properly rehydrate the yeast with GoFerm.
If you're pouring the yeast from one judge to another you're likely disturbing some sediment with each transfer, decreasing the effectiveness of your racking. I would recommend using a racking crane to siphon the mead off the lees.
It's called lee's. I think once you move on to wine yeast, or/and ale yeast you will forget using bread yeast. It's not that great in my opinion.
7 out of 4 people have a hard time using their hydrometer!