Some of the best bread makers often work with a secret ingredient - e.g. a yeast starter that has been passed down for generations.

Jesus told his disciples to beware of the “(ζύμης) yeast of the Pharisees” - i.e. their teachings (Matt. 16:6, 11; Mark 8:15; Luke 12:1). The conventional interpretation is that the symbolism Jesus meant is that of yeast used in bread.

However, yeast starters are also used in beer and wine making. For example, Christian blessings of wine being crushed at harvest time have included bottles of wine (with residual yeast) from previous vintages being poured into the juice of newly pressed grapes going into fermentation vats. Indeed, without good yeast used in wine making the resulting beverage fermented from wild yeasts can sometimes be toxic - resulting in headaches and even causing health problems.

Are there any Bible commentaries that broaden the scope & analogy of Jesus' reference to yeast to include more than just yeast used in bread making? If not, how do we know the Jesus was just thinking about just bread yeast in his teaching about the Pharisees?

For example, with wild yeasts in wine making, there a chance that things can go really bad or really good in the fermentation process. With the Pharisees and other leaders (Sadducees) there were some good teachings, but also some pretty wild teachings that resulted in sour grape outcomes.

Likewise today, one might argue, that there is a tendency in even mainstream religious institutions & leaders to have teachings that are pretty wild. As a result, an argument can be made that this has yielded a sour (i.e. hyper critical) skeptical or unbalanced graceless legalistic approach to the Christian faith.

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    Yeast is only ever associated with bread-making. There is no Biblical association between beverages and yeast. End of story.
    – Dottard
    Commented Dec 5, 2021 at 8:59
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    How do. you know that yeast was not associated with beer & wine making in Bible times? The rising of the grape must during the fermentation process and the smell of wine yeast is very similar similar to what happens with yeast in bread making. We have recipes for beer making that go back centuries that involve the use of starters (i.e. yeast).
    – Jess
    Commented Dec 5, 2021 at 16:38
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    I am speaking of the text of the BIBLE - there is no association of yeast with beer and wine in the bible.
    – Dottard
    Commented Dec 5, 2021 at 20:21
  • It is a fair question, but would be mostly relevant from the practices of ancient Egypt rather than Israel. Beer is referenced in the Old Testament, so there would been some knowledge of yeast culture fermentation. Thus @dottard's perspective can't be absolutely correct, but in context the warning is leaven versus unleavened bread likely within the backdrop of the Exodus. Wine fermentation at least in ancient times would have been free of a 'bread yeast culture' BTW. I've put forward a detailed answer. I absolutely understand beer is perceived as a less 'righteous drink' ;-)
    – M__
    Commented Jun 26, 2022 at 19:46

5 Answers 5


Look at the full context. It clearly states the leaven of bread.

When the disciples reached the other side, they had forgotten to bring any bread. 6 Jesus said to them, “Watch and beware of the leaven of the Pharisees and Sadducees.” 7 And they began discussing it among themselves, saying, “We brought no bread.” 8 But Jesus, aware of this, said, “O you of little faith, why are you discussing among yourselves the fact that you have no bread? 9 Do you not yet perceive? Do you not remember the five loaves for the five thousand, and how many baskets you gathered? 10 Or the seven loaves for the four thousand, and how many baskets you gathered? 11 How is it that you fail to understand that I did not speak about bread? Beware of the leaven of the Pharisees and Sadducees.” 12 Then they understood that he did not tell them to beware of the leaven of bread [τῆς ζύμης ⸂τῶν ἄρτων], but of the teaching of the Pharisees and Sadducees. (Matt 16:5–12, ESV)

Yeast related to brewing is not mentioned in Windisch, H. (1964–). ζύμη, ζυμόω, ἄζυμος. G. Kittel, G. W. Bromiley, & G. Friedrich (Eds.), Theological dictionary of the New Testament (electronic ed., Vol. 2, p. 902). Grand Rapids, MI: Eerdmans. This book discusses the etymology of Greek words as used in the New Testament.

  • I gave this a up vote as it’s a good start. But I’m still looking for why it couldn’t be a synecdoche of sorts, considering the wide use of yeast in beverages.
    – Jess
    Commented Dec 5, 2021 at 14:50
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    It's doubtful that anyone knew that yeast was even involved with wine making. Grapes have yeast on their skins naturally (as do the toes of the people stomping the grapes), so it wouldn't have occurred to anyone that there was any need to use yeast to make wine. Commented Dec 5, 2021 at 16:35
  • My understanding is yeast for bread is a leaven, but leaven refers to making bread rise, not brewing alcohol.
    – Perry Webb
    Commented Dec 5, 2021 at 21:37
  • @Ray I’m not so sure, as the root word of ζύμης (yeast) conveys the idea of boiling. This is precisely what grape juice looks like when it ferments. Modern Biblical wine makers use “designer yeast” sourced from famed wineries. Whether ancient wine makers used bottles of wine as starters from previous vintages and/or other locations (complete with residual yeast, as they would not have been filtered) as starters is an open question.
    – Jess
    Commented Dec 6, 2021 at 4:39

For the purpose of Jesus' illustration, it was utterly irrelevant what kind of yeast he had in mind, let alone any particular purpose that yeast was to be used for.

Yeast - any yeast - any amount - any process it was to be involved in - would serve Jesus' example perfectly. Everybody he spoke to knew all about yeast and its usage in those days, so that he chastised them for dwelling on literal yeast and thereby missing the whole spiritual point of the spiritual truth he was teaching them.

False spiritual teaching that spread like yeast was what they were to be alert to. Same then as today, irrespective of any ideas you have about literal yeast. There's no need to have a bee in your bonnet about this point, otherwise you might get stung by it. Let it go.

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    👍🏼Anne writes: "Yeast - any yeast - any amount - any process it was to be involved in - would serve Jesus' example perfectly." That's what I am thinking. Of course, the disciples were primarily thinking of yeast used in bread making. But the illustration could easily apply, out of its immediate habitant related to the shortage of bread, to that of yeast in general - used in other contexts.
    – Jess
    Commented Jun 27, 2022 at 18:31

Generally speaking Jesus used a number of physical necessities for life to represent and parallel with "spiritual" necessities for life.The foremost among these were bread and water. Food and drink. Everyone knows physical animals need food and drink to survive and live in the physical world and Jesus used these basic human staples of bread and water as metaphors for the equivalent necessities for life in the spiritual.


John 6:35 I am the bread of life,” Jesus told them. “No one who comes to Me will ever be hungry, and no one who believes in Me will ever be thirsty again.

There are countless other scriptural referrences for bread and water I can make here too many to list but essentially its about "spiritual sustanance". The base essentials required to survive.

Jesus also uses several references to "leven" and "yeast" which speaks explicitly about the "expanding" properties that are kind of unique to bread and similar food products. How it makes bread grow much larger and rise higher. He links leven expanding in bread with seeds growing into large trees in the parables given in Matthew 13:32.


The kingdom of heaven is like a mustard seed that a man planted in his field. although it is the smallest of all seeds, yet it grows into the largest of garden plants and becomes a tree, so that the birds of the air come and nest in its branches. He told them still another parable: “The kingdom of heaven is like leaven that a woman took and mixed into three measures of flour, until all of it was leavened.”

My understanding is in both cases that the "seeds" and "yeast" is basically used metaphorically for "teaching" or "principles". Gods teaching and principles may start out and seem very small. But if you "plant" them or "mix" them into yourself it will cause huge expansion because they are life giving. That small seed grows into a giant tree and the measure of dough will expand significantly into large serving of bread. Similar sentiments are expressed in his feeding of the 5000 and 4000 where he takes small quantities of bread and expands them into huge quantities to feed large crowds.

So based on the parables Jesus used and the context in which Jesus spoke I believe he used the "Yeast" or "leven" symbology specifically in relationship with his parable of the bread. The "Yeast" of the pharisees is there "teaching", "principles" and "actions" which did not align with Gods. Specifically he said the pharisees yeast was "Hypocracy". They did not practice what they preached and so there bread did not expand and grow the bread like the yeast of God.

Then they understood that He was not telling them to beware of the leaven used in bread, but of the teaching of the Pharisees and Sadducees

Beware of the leaven of the Pharisees, which is hypocrisy.

Mat23 Then Jesus said to the crowds and to his disciples: “The teachers of the law and the Pharisees sit in Moses’ seat. 3 So you must be careful to do everything they tell you. But do not do what they do, for they do not practice what they preach.

You have also mentioned wine and Jesus did also use the metaphor/parable of "wine" extensively but my understanding it was never linked to Yeast. His use of wine is more linked with the transformation process of sacrifice. The "Crushing" and fermentation to turn it into something more "potent". (Similar to the metaphor of "oil" production). It involves "Sacrifice" and often painful and difficult transformation of the original substances. Some of the meaning of this was more self evident at the time because the people were closer and more involved in the production process for these substances. They stomped the grapes to produce wine, the crushed the olives to produce olive oil and they ripped the bark off the trees to produce the resin used in Frankincense. I'm not aware of any parables where yeast is explicitly used in relationship to wine or beer so I do not see this as applicable.

  • I gave you an upvote as you had some good thoughts.
    – Jess
    Commented Dec 5, 2021 at 14:52

The yeast Jesus refers to is any yeast stored in the home, because he's making an analogy to the passover in Exodus:

Exodus 12:12 “On that same night I will pass through Egypt and strike down every firstborn of both people and animals, and I will bring judgment on all the gods of Egypt. I am the Lord. 13The blood will be a sign for you on the houses where you are, and when I see the blood, I will pass over you. No destructive plague will touch you when I strike Egypt.

14“This is a day you are to commemorate; for the generations to come you shall celebrate it as a festival to the Lord—a lasting ordinance. 15For seven days you are to eat bread made without yeast. On the first day remove the yeast from your houses, for whoever eats anything with yeast in it from the first day through the seventh must be cut off from Israel.

Essentially the absence of yeast in the homes of Israelites was an sign of acceptance of God's forgiveness. Each Israelite had a choice: continue doing as you normally do (make bread with yeast), or stop and change their behaviour to obey God.

The Pharisees were given the same choice with Jesus' teaching: continue following their own invented rules and regulations, or listen to Jesus, repent and accept forgiveness.

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    – agarza
    Commented Dec 6, 2021 at 1:53

OP answered in two parts. Firstly the historical practices of the day, secondly the direct exegesis. The correct translation provided be @PerryWebb is clearly the answer and key to this passage and must taken as a direct reference to the Feast of the Unleavened Bread.

On the translation we have which is 'yeast' and possibly not the best translation, then this might work as a translation within the broader understanding of yeast culture fermentation ...

Historical practices of fermentation Israel versus Egypt To answer @Jess, the confusion regarding the role of 'yeast' (not leavened bread) this would be relevant to Egypt at this point in history. For example, the Book of the Dead for Ka (tomb builder) and Merit (Ka's wife) makes it explicitly clear beer consumption was a dietary staple for the regular working man (women dunno) in Egypt because Ka repeatedly requested this for his afterlife and would have commissioned their Book because he outlived his wife. Ka would have received part of his wages in barley, thus they would have needed yeast to ferment it. I do understand Egyptology is probably out of bounds here, so I'll not expound the example further.

There are few references to beer drinking in the Old Testament, albeit Proverbs 31:4-7 is certainly one of them (implying beer was pretty common) and I'm not aware of any in the New Testament. There are frequent references to wine/vineyards in the Old and New Testament most notably the Last Supper, but key issue is that the fermentation process is very different to beer.

Beer needs a bread style yeast culture, otherwise (generally) its just barley water. Wine works because grape skins carry their own natural yeast (that dusty stuff on grapes is yeast). Thus all thats needed to make wine is to squash 'em and leave it, the yeast on the skin mixes with the sugars within the grapes. I accept a lot of modern wine making (not all) for exact branding and quality control is highly unlikely to rely on the variation from wild yeast.

The relevance is as follows: given the translation we have there would have been little ambiguity (probably none) with the use of a yeast culture as a method of fermentation for Israelites at this point in history. Thus, I take the point that the same yeast used for bread can be used for fermentation - and ancient Egyptians would have likely followed this practice to make beer, but not the Israelites because thats not how they made wine.

The translation 'Beware the leavened bread' (heavily paraphrased) has very different meaning however ...

Biblical exegesis Just to further @Chengarda comment, the Feast of the Unleavened Bread must be central to the exegesis of the passages of Matt. 16:6, 11; Mark 8:15; Luke 12:1

The presence of bread associated with yeast in any house for anyone (Jew or Gentile) during the Festival resulted in being 'cut-off' from Israel (Exodus 12:15; 19 RSV [below]). Whether the penalty was observed in first century Israel under Roman occupation, who knows, but there must have been significant diligence.

Yeast-risen bread, whilst not prohibited under the Mosaic law, is very bad news indeed if its in the wrong place at the wrong time. Calling someone 'yeast-risen bread', i.e. their teaching, is extreme. If this stuffs in your house at Festival time you're 'cut-off' from Israel.

The precise prohibition on eating yeast-risen bread appears complex and my reading is 3 weeks based Exodus 12 (7 days + 14 days), but could be 14 days in total. The first 7 days of the Feast strictly prohibiting any leavened bread being within the house: I assume versus Exodus 12:19 (RSV) re-refers to the first seven days of this feast and this is where the maximum penalty appears to kick-in.


14 “This day shall be for you a memorial day, and you shall keep it as a feast to the Lord; throughout your generations you shall observe it as an ordinance for ever. 15 Seven days you shall eat unleavened bread; on the first day you shall put away leaven out of your houses, for if any one eats what is leavened, from the first day until the seventh day, that person shall be cut off from Israel.

17 And you shall observe the feast of unleavened bread, for on this very day I brought your hosts out of the land of Egypt: therefore you shall observe this day, throughout your generations, as an ordinance for ever. 18 In the first month, on the fourteenth day of the month at evening, you shall eat unleavened bread, and so until the twenty-first day of the month at evening. 19 For seven days no leaven shall be found in your houses; for if any one eats what is leavened, that person shall be cut off from the congregation of Israel, whether he is a sojourner or a native of the land. 20 You shall eat nothing leavened; in all your dwellings you shall eat unleavened bread.”

Summary In my personal opinion, this is a poor translation from two perspectives:

  1. The translation is antiquated, given the historic application of yeast culture fermentation is not generally understood (why should it be). Whilst the translators from William Tyndale onwards might have had a strong understanding of this, this cannot be assumed.

  2. Furthermore the translation takes us away from the shear intensity of Jesus' words. This is gut-punch to the Pharisees. There is no way anyone should go near their teaching, which was central to their very their role.

I've done the tour BTW to pre-empt the welcome message.

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    The answer would be in the 26 volumes of Mago's viticulture (doubtfully common knowledge, but if it ain't in there no-one knew). Natural SO2 production from yeast is strain specific BTW.
    – M__
    Commented Jun 27, 2022 at 6:43
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    -M___ I have used Renaissance's hydrogen sulfide-preventing yeast in years past for crafting my commercial "award winning" wines. renaissanceyeast.com/en/about/faq It's possible that many of the ancient Romans & Greeks had bad yeast that they were working with. It's interesting the Armenian church never had to cut their sacramental wines with water to make them palatable. That might be because their wine making and yeast was better.
    – Jess
    Commented Jun 27, 2022 at 18:59
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    Reasons for why some of the ancient Greeks & Romans added water to their wines can be found here: history.stackexchange.com/a/69091/52337 Bad yeast resulting in the causing headaches could certainly be a factor in why the wines were commonly watered down in ancient antiquity.
    – Jess
    Commented Jun 27, 2022 at 19:10
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    Thanks it appears historically dynamic. Isaiah 1, "Your silver has become dross, your choice wine is diluted with water." ... that is interesting, he's using this as a term of judgemental wrath. Glad to hear about your choice awarding winning wines. Don't dilute them with water! ;-)
    – M__
    Commented Jun 28, 2022 at 3:24
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    - M Yes, at some point the returning exiles from ancient Persia started to dilute their wines. I suspect that they were forced to water them down due to cases of zygosaccharomyces bailii, brettanomyces, etc. Jesus most likely grew up tending vines and making wine. I suspect he knew what to avoid in the fermenting of great wines.
    – Jess
    Commented Jun 30, 2022 at 22:59

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