Yekke : “4. You keep mentioning “unless you do something considered a hefsek”. Simply deciding to stop eating constitutes a hefsek. When you finish eating and bentch, and you don’t have in mind to continue eating, I think that would be a hefsek.”
Yekke, the halacha is that the bracha is chal forever (or until the end of the day) unless you do something to create a hefseik.
Simply deciding to discontinue eating is not necessarily a hefseik. According to Rav Elyashiv as quoted in “V’zos Habracha” and requoted in the Dirshu Mishna Berurah (Siman 179, #10 (depending on the edition)quoting “Vzos Habracha” Chapter 20, “Heseich hadaas m’achila u’shtiya א ) most of the time it would not be considered a hefseik nowadays.
Regarding a bracha achrona, the bracha achrona itself can create a hefseik regardless of whether or not you intended to continue eating ( I believe it’s a machlokes and we posken to be choshesh for both views).
The issue here was that “al hamichya” is not the bracha achrona for rice, so perhaps it doesn’t create a hefseik for rice, and if someone made an al hamichya on the regular mezonos, perhaps they should be able to eat rice now even if they hadn’t started eating rice beforehand.
I was saying that that doesn’t make sense since then they would be able to eat rice 5 hours later even if they hadn’t specifically had rice in mind (as long as they had in mind that the rice should be chal on anything). You are saying that they wouldn’t be allowed to eat rice 5 hours but that they would be in your case (even if he hadn’t started eating rice). What is the difference between the two cases?
Maybe there is a difference (and therefore a reason why the svara is not a good svara) but I don’t think you’ve given one yet.
Is your point that in one case he specifically had in mind to continue eating and in one case he didn’t? That could be, but it seems shvach to me,( esp. since in general if one makes a bracha achrona with intention to continue eating, the bracha achrona might still create a hefseik) If you started eating the rice, you can have in mind that the al hamichya should not go on the rice , but if you didn’t start eating the rice yet, then you can’t have in mind that the al hamichya doesn’t go on the rice since you didn’t eat any rice yet.
In any case, I think that I originally stated that this wasn’t necessarily a “proof” but just a “support”.