Commercial factories have managed to produce substitutes for practically everything Chametz, from shawarma wraps to pizzas and buns, cakes, cookies, and everything in between using Matzah flour, potato starch, corn flour, rice flour, teff flour and many other ingredients.
There is little taste difference in baked goods during Pesach, and the taste is only getting better each year. Leavening agents are of course used in many of these products and it seems like eating on Pesach is all about beating the system with a variety of pseudo-Chametz. It seems that now is the perfect time to reconsider what Chametz really is, and why even regular cakes and cookies, surprisingly, aren’t really Chametz.
What exactly is Chametz?
The Torah is quite vague regarding the precise definition of Chametz and which types of grain fall under this category. Our Sages in the past laid down different guidelines such as that Chametz can only occur in five types of grain: wheat, barley, oats, spelt, and rye. They also ruled that it is not the “physical leavening of the dough” which creates Chametz, but rather it is the dough that fermented by the addition of water that is Chametz. Dough that fermented does indeed rise, but such rising is only one of the signs that the dough has undergone a chemical change known as fermentation. The definition of fermentation is the conversion of the dough’s sugars into carbon dioxide and alcohol by yeast. This same sugar conversion- fermentation can occur in flours of other grains not included in the five mentioned above, as well as in other substances such as wine. However, the Sages limited the prohibition only to the fermentation of the five species of grain listed above. It must be noted that from ancient times until the 19th century, commercial yeast was not available (nor was baking powder/soda), and in order to bake leavened bread, a sourdough (שאור in Hebrew), lactobacilli (such as yogurt or buttermilk), or beer/wine was needed to be added to the dough to speed up the long fermentation process.
If Chametz meant anything leavened (even unfermented), all kosher for Pesach cakes and cookies sold today could never receive kosher certification. In fact, the late Rabbi Ovadia Yosef permitted using baking soda as a leavening agent in Matzah Ashira (egg/enriched matzah) since the baking soda only produces carbon dioxide which expands the dough, however, it does not cause the dough to ferment – sugars in the dough are not converted into carbon dioxide and alcohol:
“ומה שכתב עוד הרב נר”ו שמכיון שנודע שמערבים בעיסה חומר כימי להתפיח הבצק, הרי זה דומה לשמרי יין שכתבו התוס’ פסחים (כח ב) ד”ה מחמת, שמחמיצים. ותמיהני עליו, כי מי הנביא שאמר לו שהחומר הכימי הזה יש לו איזו שייכות כל שהיא לשמרי יין, וכבר באו לפנינו שני אנשים, יראי שמים, מן המומחים הבקיאים בדבר, והסבירו בבירור גמור שחומר זה אינו משפיע על הבצק להחמיצו כלל, ואינו אלא כמנפח במשאבה מבחוץ, שגורמת ניפוח והתפחת הבצק, וחימוץ שאסרה תורה הוא ענין אחר לגמרי, שבהתחבר קמח דגן עם המים ושוהה בו זמן מסויים משתנה ההרכב הפנימי של הקמח, ומתחיל להחמיץ. אבל בנידון דידן ההתפחה אין לה כל שייכות עם חימוץ כלל וכלל, אלא רק מראה שהשתחרר הגאז שבא מבחוץ, וגרם להתפיח, מבלי שישנה במאומה את הבצק ממש. ושזה ברור. וידוע שאין ההתפחה לבדה סימן לחימוץ, וכמ”ש הרמב”ם (פ”ה מהל’ חמץ ומצה ה”ב): “מי פירות בלי מים אין באים לידי חימוץ שאפילו הניח הבצק כל היום ושהה עד שנתפח הבצק, מותר באכילה, שאין מי פירות מחמיצים אלא מסריחים”. ע”כ.” (שו”ת יביע אומר חלק ט – אורח חיים סימן מב)
Rabbi Yosef’s ruling demonstrates that the rising of the dough alone is not a sign that Chametz has been created.
During fermentation and baking, not only does the dough rise, its taste greatly improves due to the alcohol produced during fermentation. This is one of the biggest differences between using baking powder (or baking soda) which only expand the dough and cause it to rise, and yeast which causes real fermentation.
Besides adding true leavening agents (sourdough, yeast organisms, etc.), another way to create Chametz is to leave it out for a long period of time. The dough will begin to ferment by itself if left out long enough.
So, are Cakes and Cookies really Chametz?
Given these facts, why should homemade cookies and cakes – whose recipes do not call for yeast – be considered Chametz? If the dough doesn’t ferment before baking or in the oven (because of the short baking time and high temperature – see below) and only physically rises (just as in Matzah flour cakes made with baking powder), why then should these cookies be Chametz?
Well, actually they shouldn’t be Chametz at all.
Get ready, put your Chametz phobias aside and read on to see why:
- Yeast cells are destroyed above 60-80°C (140-176°F)
Because of the high temperature inside ovens (generally used at about 300 – 500°F) dough inside a hot oven cannot become Chametz. At low temperatures of 60-80°C (140-176°F) yeast cells die and therefore become unable to ferment dough. This is true of both external leavening agents (sourdough, yeast cells) and internal fermenting abilities.
- You may use your home oven
During baking there is no need to have the oven at extremely high temperatures because in any case the dough can no longer be fermented after being exposed to over 80°C. Therefore, no change in temperature is needed from all-year round recipes. This brings up the possibility of baking in a regular home oven. Nowadays, the majority of Jews are obviously hesitant regarding home baking of Matzah for Pesach (and even more so for baking cookies(!) on Pesach). However, one obviously does not need a commercial machine-Matzah oven running at approximately 300°C(572°F) or handmade Shmura Matzah ovens running at extraordinary temperatures of 315-426°C (600-800°F), or even 704°C (1300°F)!!! Interestingly, according to halachic authorities in the late 1800’s, ovens used for baking Matzah were running at much lower temperatures such that paper couldn’t burn in them (i.e. less than 230°C/446°F), which is a lot higher than any cake or cookie recipe even requires! In addition, it is interesting to note that before the commercialization of Matzah a little over a century ago, Jews all over the world would bake fresh Matzah during Chol HaMoed as well, at home (especially before Shabbat in order to have extra Matzah for לחם משנה). This is because the original soft Matzah becomes hard to chew after a day or two. Putting all this together, we can conclude that an ordinary home oven is suitable for baking anything from Matzot to cakes and cookies on Pesach.
- 18 minutes or 48 minutes? or longer?
Halachically, dough only becomes Chametz if it’s left untouched for a certain period of time. Though it is widely assumed that this period is 18 minutes, many contemporary authorities, including Rabbi Yehoshua Boch and Rabbi David Bar Hayim, have proven (based on accurate manuscripts of the Talmud Bavli as well as the Talmud Yerushalmi) that this period is more like 48 minutes and maybe even longer. Whatever the precise length of time may be, when baking cookies and cakes there is no need to leave the dough lying around for as long as even 18 minutes. Once the cookie-dough is ready and the oven is preheated, one can begin baking immediately without any chance of the dough becoming Chametz. Using a regular home cookie recipe, the entire process from start to finish is only eight to twelve minutes.
- You don’t need Kosher for Pesach flour
Did you ever see Kosher for Pesach flour in your local kosher supermarket? I’m not talking about Matzah flour. I’m talking about REAL flour. Contrary to what many people mistakenly assume, flour itself isn’t Chametz. Indeed, Matzah itself is made from flour! That being said, regular flour is made from wheat kernels that have undergone tempering, being lightly sprayed with water and then left to stand for a few hours until the moisture penetrates through to the endosperm. This process helps in separating the bran from the endosperm. This tempering process, during Talmudic and Gaonic times, involved actually soaking the grain in water for a short amount of time before milling. With today’s improved technological methods, the wheat is sprayed with just enough water for only a few seconds with extreme precision to barely dampen the kernels. According to many experts in this field, there is no chance of the wheat fermenting in this way. Some halachic authorities today conclude therefore that regular flour that we use all year long is not Chametz. Rabbi Moshe Vaya, author of the book series “בדיקת המזון כהלכה” writes the following,
“לדעת מומחים רבים בתהליך הלתיתה הנהוג בימינו החיטה אינה מגיעה לידי חימוץ היות ובניגוד לעבר שהיו משהים את החיטה באמבט מים, בימינו מתיזים על החיטה באמצעות תרסיס מים בכמות מדויקת , עם בקרה אלקטרונית, תהליך הנמשך 5 שניות בלבד ולאחר כ- 30 שניות אין בחיטה כדי טופח על מנת להטפיח.”
Although he doesn’t say that one may use this flour to bake Matzah on Pesach, he does say that it is not Chametz at all and one need not sell it or get rid of it before Pesach. Perhaps he is concerned that there might still be a tiny chance that a few wheat kernels got accidently sprayed with a bit more water and there might be a small pebble of Chametz in the huge sack of wheat. However, even with this concern, if we combine the halachic understanding of the modern tempering process with the Shulchan Aruch’s opinion that a tiny bit of Chametz (less than 2%) in a mixture is negligible (בטל בשישים) before Pesach, there is absolutely no problem using this flour to bake Matzot or anything else unfermented on Pesach.
But what about just using Shmura flour, the same flour used to bake our Shmura Matzah? Or using regular kosher for Pesach flour, the same flour used to bake regular Matzah? Obviously, if we could buy Shmura flour easily at our local supermarkets we would. However, it’s not for sale unless you have “connections” or are opening up another Matzah factory and are willing to buy wholesale quantities. So until this flour appears at your local supermarket, don’t hesitate to use regular flour. It’s not Chametz.
 Yerushalmi Pesachim 2:4 (Vilna Edition)
 This partly explains why beer is also considered Chametz.
 See Bavli Pesachim 35a and Rashi ibid.
Regarding Mei Perot (other liquids such as grape juice, oil, and honey), some Rabbis prohibited as well and decreed that they can also cause wheat to ferment.
 For a detailed analysis of the reasons behind Chazal’s ruling see:
“חמשת מיני דגן”, זהר עמר, הוצאת מכון הר ברכה, תשע”א pp. 88 – 102
 Chazal also said –
“תנו רבנן, אלו דברים שאין באין לידי חימוץ: האפוי, והמבושל, וחלוט שחלטו ברותחין.” (פסחים לט:)
 “The Halachic Acceptability of Soft Matzah”, Rabbi Dr. Ari Z Zivotofsky, Dr. Ari Greenspan
 Nowadays some people freeze soft Matzah before Pesach to keep them fresh, but obviously, this luxury did not exist in the past.
 Bavli Pesachim 46a
See also: http://www.tzohar.org.il/?p=2163
 O”H 447:4