Is it permissible to use sourdough starter to leaven bread?

I.

Sourdough starter is a natural mixture that is used to leaven bread. Basically, it is composed of flour and water, which are left to ferment through the action of microbes that naturally exist in the air and on the surface of the flour.

Sourdough starter consists of wild yeasts and beneficial bacteria (such as lactic acid bacteria or Lactobacillus). These microbes feed on the sugars in the flour and produce carbon dioxide, which makes the dough rise, earandned natural acids which give the bread its distinctive sour taste.

After fermenting, the starter contains a very small amount of alcohol, because the wild yeasts produce ethanol, but this amount is tiny, as studies indicate that the percentage of ethanol in the fermented dough is usually between 0.1% and 0.5% under most normal circumstances, and may reach higher amounts in some specific instances during fermentation, but the percentage remains very low, and when the bread is baked, the alcohol evaporates almost completely because of the heat, because ethanol evaporates at a temperature of 78°C. What is left of the sour taste comes from the acids that are produced by the beneficial bacteria during fermentation, and not from the alcohol.

II.

Based on the above, it is permissible to use sourdough starter, because the percentage of alcohol in it is very small and it is completely used up, so it does not have any impact of causing intoxication when using it, and the alcohol completely disappears when the bread is baked.

People throughout the ages have used yeast to leaven dough, and that is a widespread practice to which no one has objected.

The jurists have stated clearly that it is permissible to blend dough and yeast, even though it was not permissible to pay in advance (salam transaction) for these items to be delivered later, because of the widespread need for that.

Shaykh Sulayman al-Jamal said: It is permissible to lend dough, even sour yeast, by weight, for the reason mentioned above.

His words “for the reason mentioned above” mean, because of the widespread need for that.

See: Hashiyat al-Jamal `ala Sharh al-Manhaj, 3/258.

Al-Hasakfi said: In Al-Qunyah it says that borrowing yeast by weight is permissible.

And it is appropriate that it should be permissible to borrow yeast without weighing it…

Ibn `Abidin said in his Hashiyah: This is the view that we prefer, and beware of estimating the weight because that is not permissible [rather it should be weighed properly].

End quote from Radd al-Muhtar, 5/167.

To sum up:

People throughout the ages and in different regions have added yeast to bread dough with no objection from any of the scholars, and yeast only works by fermentation, and the process of fermentation is done by all types of yeast.

Shaykh Muhammad Abu Zahrah (may Allah have mercy on him) was asked: In Jumada al-Ula 1385 AH, you issued a fatwa stating that beer is prohibited. What do you think about brewer’s yeast that is used to leaven dough?

He replied: Brewer’s yeast, as far as I know, is not bought for the purpose of becoming intoxicated, nor does it cause intoxication; rather it is used to leaven dough, so we do not think that it is prohibited.

But it is better for those who want to ferment something to rely on natural processes that cause fermentation with the passage of time, as the women in the villages do, so as to be on the safe side and because the Prophet (blessings and peace of Allah be upon him) said: “Leave that which makes you doubt for that which does not make you doubt.” [Fatawa ash-Shaykh Muhammad Abu Zahrah, p. 684].

End quote from Mawsu`at Sina`ah al-Halal, 3/133.

Shaykh Ibn `Uthaymin (may Allah have mercy on him) was asked: What is the ruling on the yeast that they add to flour to leaven it and make it easy to cook? Some people say that it is khamrah (alcohol) and it is not permissible to use it.

He (may Allah have mercy on him) replied: My response to them is that there is nothing wrong with putting yeast in dough in order to leaven it, because this does not affect it at all. Moreover, I do not think that this yeast causes intoxication if a person were to consume it and eat it.

The basic principle regarding all kinds of food, drinks and clothing is that they are permissible unless there is proof that they are prohibited, because Allah, may He be Exalted, says: {It is He Who has created for you all things that are on earth; furthermore He turned to the creation of heaven, and made seven heavens. And He has knowledge of all things} [Al-Baqarah 2:29].

So there is nothing wrong with adding yeast to the dough to leaven it.

End quote from Fatawa Nur `ala ad-Darb, 20/2.

The Permanent Committee for Issuing Fatwas was asked about selling vinegar that contains 6% alcohol; what is the Islamic ruling on that?

They replied: It is soundly narrated from the Messenger of Allah (blessings and peace of Allah be upon him) that he said: “Whatever causes intoxication in large amounts, a little of it is prohibited.” So if a large amount of this vinegar would cause intoxication, a small amount of it is prohibited, and it comes under the same ruling as khamr (alcohol). But if a large amount of it would not cause intoxication, in the sense that the percentage of alcohol is very small, then it does not seem that it would have any effect, so there is no reason not to sell it, buy it and drink it.

End quote from Fatawa al-Lajnah ad-Da’imah, 13/291.

We have previously discussed in detail on this website the ruling on adding yeast to dough. See the answer to question no. 142032.

And Allah knows best.