What about soaked matzah, and rich matzah? Are those too unnecessary concerns?

Soaked matzah, yes. Rich matzah, according to some opinions (the Rema), is actual leaven and not merely a concern.

I saw on the internet a responsum of yours in which you say there is no reasonable basis for the prohibition of legumes.
Is there not an issue here of “when the reason is annulled, the enactment is not annulled”?

First, the rule that “when the reason is annulled, the enactment is not annulled” is itself not absolute (see dozens of examples where the medieval authorities changed enactments in the last chapter of Neria Gutel’s book Changes in Nature). Second, that rule applies to enactments or decrees. An enactment or decree is the result of an explicit determination by an authorized religious court (for the Jewish people as a whole, the Sanhedrin or the Talmud itself, which is regarded as a Sanhedrin). That is not the case with legumes. There was never any religious court that established a prohibition on legumes. There was simply a situation in which grains of leaven got mixed into legumes, and therefore people refrained from eating them.
In short, my claim is that contrary to the common discourse, there is no enactment here and no decree either. Who enacted or decreed this? Was there a Sanhedrin? And even without a Sanhedrin, did the sages of that generation enact this? In a certain place people simply refrained from legumes because there was concern that leaven had gotten mixed in. Now, and in our locale, there is no such concern, and therefore there is no prohibition.
This is similar to someone who found leaven in a certain room in his house and therefore is careful not to bring kosher-for-Passover food in there. Now he cleaned the room; is it still forbidden for him to bring food in there? Alternatively, in a world without cars, must one still cross the street only at a crosswalk?
As stated, the situation would be different if a council of sages had convened and determined that one must cross only at crosswalks. In that case, another assembly would be needed to repeal the original enactment. But regarding legumes there is no indication whatsoever that anything like that happened (and certainly not a Sanhedrin), and therefore it is not something enacted by formal count that requires another formal count to permit it.
The “decree/enactment of legumes” was born in the overheated minds of people who are afraid of changes (the Reform reflex). There is no such thing. True, there are formulations in the medieval authorities that imply that this is a decree, but those are astonishing statements, since they have no basis, as explained above.
See further, column number 2 on the site:

https://mikyab.net/%d7%a2%d7%9c-%d7%92%d7%96%d7%99%d7%a8%d7%aa-%d7%a7%d7%98%d7%a0%d7%99%d7%95%d7%aa-%d7%a9%d7%9e%d7%a8%d7%a0%d7%95%d7%aa-%d7%95%d7%97%d7%99%d7%9c%d7%95%d7%9c-%d7%94%d7%a9%d7%9d-%d7%98%d7%95%d7%a8-2/

A. According to this, what is the Rabbi’s opinion about the seven clean days? Is that a binding custom? And what about waiting 4 days before counting the clean days? Or the Ashkenazic addition of 5 days? B. How is this different from the people of Beishan in the Talmud in tractate Pesachim, where they were obligated to continue their ancestral custom of refraining from setting sail on Fridays? Why is it binding there and not binding here? Thank you very much.

Why should those customs be abolished? Their reason still exists today. What do those have to do with our case, which is a foolish custom without any reason? The people of Beishan had the custom not to go down to a ship before the Sabbath, and it is a fine custom whose reason is still in force.

Rabbi Michael, can you cite precedents for other customs that were abolished over the generations because their reason ceased to apply? (Other than translating the Torah reading.) The cornerstone of your words is that a custom—or “concern”—whose reason no longer applies is automatically annulled, and in my opinion that is really not so simple.

First, I distinguished between a custom and a concern. A concern is not a custom but conduct meant to prevent a local problem. There are countless examples of concerns that were annulled. Every pothole in the road near your house is an example of this. After the municipality repairs it, drivers do not continue—and also do not need—to go around that spot. I gave the example of washing the hands for something dipped in liquid, which is an actual law (more stringent than a custom). The Shulchan Arukh refers to kapparot as a foolish custom. And there are many more examples. Search Google or the responsa database for “foolish custom” and you will find plenty. But as I said, a concern is lighter than a custom and certainly lighter than an actual law.

Hello Rabbi, I asked the question about legumes in one of the forums, and this is the answer I received. What do you think?

My explanation is not, admittedly, the explanation of the medieval authorities, but the answer is simple. There was a major dispute in the period of the Mishnah and Talmud whether the grains are only the biblical grains—that is, a very rigid kind of formalism—or whether the term includes grains in general. Rabbi Yohanan ben Nuri held that all grains are included, while others held that only the five species of grain are included—practically speaking, our wheat and barley. Which means that in every place where wheat and barley were not used as grain, such as Africa, the East, and parts of the West, they could not bake matzot, and on the other hand there would be no leaven. In Babylonia they ruled like the Sages, but in broad parts of the Jewish world they ruled like Rabbi Yohanan ben Nuri and therefore continued to forbid other grains. Remnants of this ruling remained with regard to the blessing “Who creates various kinds of nourishment” over rice. So this is not at all a puzzling approach. On the contrary, the approach that excludes corn, rice, millet, and other grains is the puzzling one.

Nonsense. Is the custom to rule like Rabbi Yohanan ben Nuri? That is acrobatic interpretation whose purpose is to validate a custom that has no reason and no binding force.

The end of his remarks is incorrect, in my humble opinion. In Berakhot 37a it is explicit that the blessing “various kinds of nourishment” over rice does not stem from the position of Rabbi Yohanan ben Nuri, because according to him the blessing over rice is “who brings forth bread from the earth.” (Rice is a grain in every respect.)
And I did not understand why the position of the Sages “is the puzzling one.” Because they present “rigid formalism”?

A.H., studies of this sort are not built on Talmudic passages except as a source for various opinions. The rationales that the Talmud gives or uses to explain the opinions are its own business. He is claiming, on a scholarly basis, that the blessing over rice is connected to Rabbi Yohanan ben Nuri’s fundamental conception, even if the Talmud offered a different explanation.

That person does not present himself as a scholar (he says he is ready to bring another explanation from the medieval authorities—that is, not from the Talmud).
His words look like non-compelling speculations. How does he know that according to Rabbi Yehudah all legumes are forbidden? In Pesachim 35a he appears to forbid only rice and millet because they are close to becoming leavened (that is not Talmudic discussion but a baraita there), and in another baraita he says that rice is full-fledged leaven. And according to the Sages, rice only spoils (a dispute about reality). Nowhere does he say that all legumes are forbidden (except in Tosefta Hallah chapter 1 and Pesachim chapter 2, where “karmit” is obligated in hallah and considered matzah. But clearly that is a kind of rice bread. Is it not odd that Rabbi Yohanan ben Nuri, in the context of the grain type, always mentions rice, while in the context of bread he consistently mentions karmit?).
The Talmud’s approach is actually far more logical. Rabbi Yohanan equates rice with the five species in every possible context—why would he back down in the context of blessings and agree to “various kinds of nourishment” rather than “who brings forth bread from the earth”?

🙂 I did not say that what he says is logical; I said that what appears in the Talmud does not necessarily impress him, as is the way of “research.” Very often what they say is implausible speculation. But unlike the words of the medieval authorities, this is “research,” so of course it is reliable and logical.

Regarding the issue of legumes, it is very worthwhile to read the chapter on this subject in the book of Rabbi Yisrael Ta-Shma, Ancient Ashkenazic Custom. There he shows that apparently the reasons for the prohibition of legumes are rationalizations for a custom that already existed, and probably are based on a dispute between the Babylonian Talmud and the Jerusalem Talmud regarding grinding legumes on a Jewish holiday (not only on Passover—and there is a hint of this in some of the early Ashkenazic responsa on the subject), which at a later historical stage also became connected with doubts regarding “stiff leaven.” In his book he shows several eye-opening matters on this subject, such as the Raavad’s gloss on kneading with fruit juice (or perhaps legumes, which are mentioned immediately before that), as well as variant readings between the Arukh and the Tosafists who quote it, but this is not the place to elaborate.

Is the Rabbi familiar with Rabbi David Bar-Hayim and his opinion on this matter?

No and no.

So he permitted it as well, long ago.
He says it may have a source in Karaite influence.
If the Rabbi wants to see, he explains it here:

I of course agree in principle. And yet, a few comments:
1. He does not address the difference between a concern and a custom.
2. His conjecture about a Karaite source sounds very speculative.
3. He relates to the custom as a local custom, but it seems to me that nowadays this is an anachronistic interpretation. In the past, when the world was static, custom followed place. Today custom follows origin. That is how it is regarding “do not form separate factions,” for example (which he also mentions at the end of his remarks).
4. His remarks about unity are complete nonsense, of course, from beginning to end.
5. I completely agree with his conclusion, that today this foolish custom takes over the entire “screen” and overshadows the real contents of Passover. Distortion of thought, waste of energy, and so on.

This is the place to bring Tosafot on Beitzah 6a, s.v. “ve-ha’idna,” who wrote that there is no need for a formal count to annul a concern:
By the way, I found Tosafot on Beitzah 6a, s.v. “ve-ha’idna,” who wrote about the difference between a concern and a custom:

“And nowadays, because there are chaverim, we are concerned”—Rashi explained that they compel Jews to do labor, and when it is a festival they leave them alone; but if they saw that Jews bury their dead, they would compel them to do labor. And now, in this time, when there are no chaverim, it is permitted. And one should not say that another formal count is required to permit it, for since this reason was due to a concern, and the concern has passed, the reason has passed. And so too we say regarding uncovered water, that it is forbidden lest a snake drank from it; and now that snakes are not commonly found among us, we drink from it even ab initio, even though it is something established by formal count. Nevertheless, Rabbenu Tam would forbid it.”

Exactly as I wrote in my column about legumes.