Citric acid is used to flavor juices, jams, candies, and various food items. In the past it was extracted from lemons and other fruit, but nowadays it is produced commercially from wheat flour.
Although during the production process the flour is initially mixed with water and may become ḥametz, at a later stage it loses its taste and appearance, is rendered unfit for a dog’s consumption, and thus loses its status as ḥametz. Some poskim therefore permit eating products containing citric acid on Pesaḥ (Yeḥaveh Da’at 2:62).
In contrast, many poskim are stringent in this case. In their opinion, ḥametz 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 ḥametz for all purposes (Minḥat Yitzḥak 7:27; Or Le-Tziyon 1:34; Shevet Ha-Levi 4:47).
The halakha follows the lenient view, and in accordance with the words of R. She’ar Yashuv Cohen, of blessed memory, the municipal rabbi of Haifa, who investigated and found that there is no concern that citric acid is ḥametz. First, the flour that starts the process does not become ḥametz since it sits in water for only six minutes – not enough time to become ḥametz. Second, the starch is then extracted from the mixture, and starch alone cannot become ḥametz. Third, 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.
The liquid dextrose is then mixed with sulfur to destroy the enzymes in it and render it inert and unable to ferment. Since it never had the chance to become ḥametz, it certainly will not become ḥametz in the future. This is the first stage of the process, which shows that the extracted starch does not become ḥametz. 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 Pesaḥ, certainly citric acid excreted by molds that digested a liquid that never became ḥametz in the first place would be kosher for Pesaḥ. This conclusion has major implications for other industrial ingredients that use wheat starch that never became ḥametz and that undergoes fundamental alterations before being reintegrated into food.