When should I remove fruit from primary?

I'm far from a flavor, or fermentation, expert... but I'm pretty sure I can anticipate what they would tell you. These types of questions are difficult to answer as we don't have your taste buds and, even worse, our taste buds are not present to evaluate your mead. When I have a doubt like this I taste daily and then remove the item in question when I'm happy with the flavor, or when the flavor is slightly intense. If the taste diminishes, as the primary continues, you then add the item in question again to the secondary and taste frequently again to get the flavor where you want it.

Hi - I've never heard, read, or experienced that any fruit with seeds should be taken out of primary, but I guess that may depend with how long you want to keep your must in primary. Actually, I've heard that seeds can be a good thing. That's not to say that it isn't possible to leave fruit in primary too long and end up with negative results. Some wine grapes have seeds, but I'm not sure if those somehow get taken out. My guess is they are likely a part of the crush and must in at least some way.

EricHartman is right in tasting your mead as you go. The challenge is knowing what a primary fermentation should taste like and if you can leave it in longer, or take it out, etc., because the mead will be changing as you go.

Personally, I feel pretty safe with fruit in primary for 2 weeks, and I've went a little over 3 weeks with fine results, but I'm generally racking off any additional fermentation ingredients pretty near when fermentation is done. This is because there's always bits of stuff I don't want spoiling in my must - even if I'm using mesh bags. If it's a traditional, I let it go a bit longer before racking of the rough lees. When adding fruit to secondary, I feel I get good fruit uptake within 3 weeks as well.

I've never experienced bitterness when using fruit with seeds (besides my first JAOM attempt, and that was from the orange pith for sure). I'm not saying it wasn't seeds with your previous experience, but you may want to consider the possibility something else caused the bitterness.

Certainly no expert but here's a few things to think about: what is happening when we add fruit in the primary? Basically we are using water to extract the flavor. Water is a reasonably good solvent for this purpose but it can take many days to extract enough of the flavor. If you add heat (boiling water) then the extraction is faster. If you damage the cell walls of the fruit by freezing the water in the fruit then the extraction is faster. Alcohol is a better solvent than water, so if you add the fruit when the alcohol level is at say, 10 or 12% ABV extraction is better. It is certainly different and you get a brighter flavor from the fruit (in my opinion).

Bottom line, you might remove the fruit after a few days in the primary if you think that most of the flavor has been extracted and is now in the mead or you might choose to add the fruit to the secondary to extract the flavors using the alcohol. But you have taste-buds. Taste the solution. When the flavors have the intensity you are looking for you can remove the fruit from the mead or the mead from the fruit.