Citric acid is used to flavor juices, jams, candies, and various food items. In the past it was produced from lemons and other fruit, but nowadays it is produced industrially from wheat flour.
Although during the production process the flour is initially mixed with water and may become ĥametz, at a later stage it loses its taste and appearance, is rendered unfit for a dog’s consumption, and thus loses its status as ĥametz. Some poskim therefore permit eating products containing citric acid on Pesaĥ (Yeĥaveh Da’at 2:62).
However, many poskim are stringent in this case. In their opinion, ĥametz only loses its status if it becomes unfit for a dog’s consumption due to spoilage. If it is intentionally rendered inedible so that it may be used to flavor foods, it is not nullified and is considered ĥametz for all purposes (Minĥat Yitzĥak 7:27; Or Le-Tziyon 1:34; Shevet Ha-Levi 4:47).
Rabbi She’ar Yashuv Cohen, the municipal rabbi of Haifa, investigated and found that there is no concern that citric acid is ĥametz. To begin with, the flour that starts the process does not become ĥametz since it sits in water for only six minutes – not enough time to become ĥametz. At this point, the starch is extracted from the mixture, and starch alone cannot become ĥametz. Moreover, citric acid is not produced from the wheat starch itself, but from molds that feed off a substance whose ingredients include a material extracted from the unleavened starch.
. This debate is very extensive, and the key questions are: is something that was batel be-shishim before Pesaĥ ĥozer ve-ne’or once Pesaĥ begins? Even if not, would a stabilizing agent (“davar ha-ma’amid”) be any different? And what if it is not the sole agent? See Yalkut Yosef, Mo’adim p. 358 which responds to Minĥat Yitzĥak’s criticism of R. Ovadia Yosef. Badatz and many other kosher-certification agencies are very strict about citric acid and similar products. Nevertheless, according to R. She’ar Yashuv Cohen’s long essay in Teĥumin vol. 1, it seems clear that there is no reason for concern that citric acid contains ĥametz. More precisely: the starch is first separated from the gluten by spinning the wheat flour in water for six minutes. As we know, it takes eighteen minutes for flour and water to become ĥametz, so the flour could not have become ĥametz in those six minutes. By then the starch has already been separated from the gluten, and it is well known that the leavening process takes place in the gluten. Thus once the starch has been isolated from the gluten, it can no longer become ĥametz. The starch is then heated to 140º Celsius until it liquefies as dextrose (also known as glucose). This heating process destroys the existing molecules and changes their composition. To dispel any doubt, an attempt was made to leaven this substance, but it was unsuccessful.
R. Halperin writes that at worst this substance can be considered ĥametz nuksheh, which is rabbinically prohibited, becomes batel in any mixture prior to Pesaĥ, and would be ĥozer ve-ne’or on Pesaĥ. According to R. She’ar Yashuv Cohen, this substance is not even considered ĥametz nuksheh, which is dough whose leavening process was halted after it began; the substance in question never even began the leavening process.
The liquid dextrose is then mixed with sulfur to destroy the enzymes in the glucose and render it inert and unable to ferment. Since it never had the chance to become ĥametz, it certainly will not become ĥametz in the future. This is the first stage of the process, which shows that the extracted starch does not become ĥametz. The next step is to place the liquid into large vats, to feed the molds. It is left until the mold has finished digesting all of the dextrose and excreted another substance: citric acid. Thus, citric acid is not a product of the starch, but a product of the mold. Just as if one used organic fertilizer that contained remnants of bread to fertilize vegetables, the vegetables would undoubtedly be kosher for Pesaĥ, certainly citric acid excreted by molds that digested a liquid that never became ĥametz in the first place would be kosher for Pesaĥ. This conclusion has major implications for other industrial ingredients that use wheat starch that never became ĥametz and that undergoes fundamental alterations before being reintegrated into food.