I want to make lemon+poppy ice cream, and I have a bag of preground blue poppy. I’m not following s specific recipe, I just like the flavour combo and had it in icecream from a shop before. Can I add them to the base when it’s hot; when it’s chilled before churning; steep them then strain them out; or do I add them to the finished icecream?
Poppy seeds have a very pleasant aroma and a bit of heat is going to do wonders to extract their flavour and aroma. I would dump them right into the end of the cooking process after you remove your custard from the heat. You don't want to cook them because you'll boil off volatiles and lose some flavour much like vanilla.
I think if you can get some lemon zest to appear in your finished product, or even as a garnish, along with the flecks of poppy it's going to look beautiful if you leave them in. Sort of a more sophisticated vanilla bean ice cream vibe.
This lemon/poppy seed recipe adds the seed to the chilled mixture before churning the ice-cream.
Other recipes seems to have more or less the same steps, add the seeds to the chilled mixture.
I would assume adding seeds would be a lot like adding other things such as cookies, candy, nuts, chocolate, etc. In those cases, I've found that it works better to add them at the end, since they can sometimes be large enough to interfere with the machine's dasher. And for softer things like cookies or brownies, or swirls of things like caramel or jam, you pretty much have to add them at the end to avoid them either disintegrating or just getting lost in the ice cream.
Some recipes say to add extras to the ice cream in the last couple of minutes of freezing in the machine, but I've found that it's better to pre-chill a ceramic bowl and then transfer all the ice cream to the bowl using a pre-chilled spoon before folding in the extras. You don't have to worry about getting the timing just right and it works better for machines where the top is covered and all you have is a small chute.
In the case of poppy seeds, you may find that they're small enough that you can add them at the beginning without interfering with anything but in general I think adding things at the end works better for me. That's the way it's done for commercial ice cream as well, where the extras are dropped into the stream of frozen ice cream as it leaves the machine.