A Closer Look: Wheat Flour

What is wheat flour?

Wheat flour is a finely ground powder made from wheat kernels. Wheat is a widely cultivated grain, and the flour is a staple ingredient in both baking and cooking. When wheat flour is combined with water, it forms gluten, which gives structure to foods such as bread, cakes, and pasta. Each type of wheat has a unique gluten content. Soft wheat is low in gluten and is typically used for cakes and pastries, while hard wheat has a higher gluten content and is mainly used in breadmaking.

How is wheat flour made?

Producing wheat flour is a multi-step process, including cleaning, tempering, milling, sifting, bleaching, and enrichment.

First, the raw wheat is cleaned to remove all impurities and foreign objects.

The wheat then goes through a tempering process where a fine mist of water is sprayed on the wheat while it passes on a screw conveyor. The wheat is then conveyed into large tempering bins for 8-16 hours to absorb the moisture. This process is done to increase the moisture level of the wheat and help with the milling process.

The next step is milling, where rollers are used to crush the grain, breaking it into smaller parts (bran, germ, and endosperm).

Then comes the sifting process, where all the broken grains are passed through sieves to separate the particles by size.

White flour is chemically bleached for a whiter color and finer crumb.

Some flours are enriched by blending a very small amount of iron and B vitamins (nutrients lost during the processing of white flour) into the flour. All-purpose flour and bread flour often contain malted barley flour, which is added to enhance yeast fermentation and improve bread textures.

What is different about wheat flour for matzah?

The production of wheat flour for kosher l’Pesach matzah is quite different as no water can be used in the milling process. The mill for matzah flour must be dedicated to Passover flour or thoroughly cleaned before the start of the process. For Shmurah Matzah, the wheat must be watched from the harvesting process to make sure it does not come into any contact with water from the moment it is cut from the ground.

What are the kashrus challenges with wheat flour?

Flour is acceptable without kosher certification as long as it is not a product of Israel. Even when the abovementioned additives are included, they are used below the threshold for bitul. Obviously, kosher certified flour will have all of the additives kosher certified and not rely on bitul.

What about regular wheat flour over Passover?

Historically, the tempering process involved soaking the wheat in water and it is mentioned in the Gemara that it was allowed as long as the wheat was kept in constant motion and ground immediately.¹ The Geonim prohibit tempering the Pesach wheat because the knowledge of tempering without making the wheat chometz was lost and there is a concern that it will not be ground immediately.²

Modern production uses a mist of water that is sprayed on the wheat. While it is much less water than what was historically used, the flour is still not suitable for Pesach.

The flour cannot be owned by a Jew during Pesach, because it was not kept in constant motion and not ground immediately.³

Some communities avoid selling chometz gamur (actual chometz) but will often include flour in their chometz sale. The Passover prohibition is only because the flour is safeik chometz⁴, not chometz gamur, since the wheat kernels do not crack from this process.

Yoshon⁵:

During the time of the Beis HaMikdash, the consumption of wheat, barley, spelt, rye, and oats was prohibited if they were “new” (chodosh). Grain that was planted before Pesach became “old” (yoshon) after the offering of the Korban Omer.

There is a halachic debate whether the prohibition of chodosh applies today, especially outside of Eretz Yisroel. In recent years, it has become more common for people to be stringent and consume only yoshon products, so there is increased demand for wheat flour that is certified to be yoshon.

During the period following Pesach, until the summer when the spring wheat reaches the market, all flour is yoshon.

Once the new spring wheat reaches the market there are different approaches to certifying flour as yoshon:

1. Mills that do not process spring wheat are the simplest to certify. The mashgiach verifies that all additives, such as enrichment and barley malt flour, are yoshon.

2. Some mills process the flour in advance but keep it in cold storage to avoid the risk of insect infestation due to the extended storage time.

3. The third option is to make special runs of yoshon flour from wheat kernels that have been kept in sealed rail cars or silos. In this case the machinery is cleaned well and flushed from any chodosh flour.

1 .ראה גמרא פסחים מ, א
2 .טור, ב”י ושו”ע או”ח תנג, ה
3 .שוע או”ח תנ”ג – שו”ע הרב סעיף כא ומשנה ברורה כז
4 .ראה בסימן תמז – מג”א יב, שו”ע אדה”ז ז, ופרי מגדים מ”ז ג
5 To read more about yoshon, see https://www.ok.org/consumers/related-mitzvahs/yoshon-qa/.

Rabbi Hendel is a member of the OK Kosher Vaad HaKashrus.