For some people in the church, the name Chorleywood will by synonymous with the New Wine Network, Vineyard Churches, John Wimber, Barry Kissell, John Perry, David Pytches and Mike Pilavachi’s ground-breaking Soul Survivor festivals.  Few of the residents, I am guessing, will have noticed, tucked away behind a high wooden fence on a main road, the Flour Milling and Baking Research Association headquarters, or heard of the invention of the Chorleywood Bread Process (CBP).  After the ravages and rationing of the Second World War, feeding Britain was not easy.  And the Ministry of Agriculture, Fisheries and Food turned to research that could produce bread on a mass-scale – ideally cheaply, and with a long-life.  Chorleywood Bread Process helped develop forms of bread that were quick to make and fast to bake, lasted a long time, and were inexpensive.  The sliced-white-loaf seen in all supermarkets is the legacy.

The Chorleywood Bread Process used dry-packed yeast.  It represented a quick, reliable, predictable, mass-market and inexpensive rising agent.  But for many people, this is not ‘real’ bread at all. Rather like the campaign for real ale, there has been a marked turn in the closing decades of the twentieth century continuing into the twenty-first century, that has sought to recover the authentic texture, taste and nourishment of real bread.  Of course, it cannot be mass-produced, and so it is normally more expensive. But the difference between a manufactured loaf and an artisan one is as night and day, or chalk and cheese.

So, to the key question: how many times does the word ‘yeast’ get used in the New Testament?  The answer may surprise you: none. The New Testament gives us around a dozen occurrences of the Greek word ζύμῃ or ζύμης (pronounced zýmē), and although many Bible translations will render that word ‘yeast’, the actual word is for ‘leaven’.  You may be forgiven for thinking the difference in translation – as we might say of the yeast itself – is tiny. Indeed, small beer? I don’t agree.

The word yeast comes from the old English word gist or gyst, and ultimately from an Indo-European etymological root simply meaning yes.   But that ‘yes’ also grew to mean to boil, foam, or bubble.  Put another way, yeast is the ingredient that turns the passive into active; the flat into flavorsome; the ordinary into the extraordinary.  However, yeast, as a discrete entity and distinct ingredient, would have been completely unknown in the kitchens and households that Jesus inhabited. Bread was not made that way; nor wine, nor beer.

The world of the ancient near-east made varieties of flatbreads and sourdough loaves.  With no yeast to hand, leaven was the only rising agent. True, and in some respects, superficially, it performs a similar task to yeast. Leaven (used as a noun) is a substance added to dough to produce fermentation, and our English word comes in part from the Latin levamen, which in literary use meant “alleviation and mitigation” but in colloquial and everyday use had the literal sense of “a means of lifting; something that raises”. It is from the root levare, meaning “to raise”, and it has passed in to our usage to describe the act of enabling something to “not be heavy”, or seeming to “have little weight”. 

As a verb “leverage” is a related term – lifting and influencing, and the verb leaven.  Leavening and leaven-ous activity excite fermentation dough or wine, and the term has come to mean something more figurative: the sense of “work upon by invisible or powerful influence”.  When we read the gospels, we assume that Jesus’ use of the term is broadly critical (say of the Pharisees) – that their leaven is a cipher for the spreading influence of something concealed; a coded symbol for the spreading nature of evil.  Most translations render the Greek word zýmē as yeast, but as I have already indicated, the bread of the world two thousand years ago was either a flatbread or a version of what we know today as sourdough.

There are other reasons the persist with translating the Greek zýmē as leaven, and not as yeast.  In Luke 13: 21 (parallel Mt 13: 33), leaven is compared to the rising agency of the kingdom of God.  So Jesus alerts us to the good aspects of leaven.  Compared to Matthew 16: 6, 11, however, and we are warned off the ‘leaven of the Pharisees’ (see also Mark 8: 15, and Luke 12: 1). Paul, writing in I Corinthians 5: 6-8 renders positive uses of leaven, as does Galatians 5: 9.  In each case, the use of leaven, whether in making wine or bread, requires knack, know-how, skill, care, calculation, experience, trial-and-error, labour and patience.

If I make one aside here, it is in relation to ‘gyst’ which we discussed earlier as yeast, but discounted as helpful.  GYST is a modern mnemonic, meaning ‘Get Your Stuff Together’ (sometimes rendered ‘Get Your Shit Together’, and is closely related to ‘get your act together’.  The agency implied in the mnemonic is: get up, get organised, and get busy. Don’t hand around or dither; sort out your life, and start living it usefully. It has also come to refer to our own completion of critical end-of-life planning issues, such as gathering essential documents like wills, and letting your children know where to find your bank details – but only after you have died.  In other words, leaven might have something to do with our organised legacy.

That brief aside has one value, namely, to ask what is it, exactly, that is quite so bad about the leaven of the Pharisees?  To answer this, one has to understand how sourdough is made.

Before we had active-dry yeast or instant yeast, our forebears used wild yeast. We still have wild yeast, as it literally lives everywhere — in the air, in a bag of flour, and on the surface of fruit such as grapes. Modern domesticated commercial yeast replaced wild yeast for most of our baking because it’s easier for companies to mass produce, and it was far easier for bakers to store and use in proofing our breads and pastries – all done in a fraction of the time, and a fraction of the cost.

A sourdough bread gets its flavour from wild yeast that is naturally found in your kitchen. This of itself may not sound interesting, until you begin to appreciate that a San Francisco sourdough will taste different to a New York one, or to one made in an artisan bakery in Oxford or London. Real sourdough has the authentic leaven that evolves from its micro-environment, and that will be distinctively contextual.

Leaven for bread is made by trusting in the natural process of the spores as they are mixed with flour and water. Leavening in sourdough is made from a mixture of flour and water; after a day or two, bubbles will start to form in the starter, indicating that the wild yeast is starting to become active and multiply. To keep the leaven happy, it is ‘fed’ with fresh flour and water over several days, until the starter-mix becomes bubbly and billowy. Once it reaches that slightly frothy, billowy stage, the starter is ready to be used for kneading.  The mixture becomes a playground for lactobacilli bacteria and wild yeast. These naturally occurring organisms work together to make enable the leavening and rising properties occur, and for the and complex flavours and textures to emerge in the baked loaf. 

So when Matthew 16: 6 records Jesus saying to the disciples: “watch out, and beware of the leaven of the Pharisees and Sadducees”, what exactly are we looking out for? Superficial translations and expositions that opt for ‘yeast’ will quickly render the meaning of the text as a warning against narrow-minded religious exclusivism and sectarianism. Of course, that could mean many things, but as leaven is meant, not yeast, then we have to accept the leaven Jesus speaks of is everywhere, and that includes the kitchens and homes of all believers. And like bread, any believer of any type can be half-baked, over-baked, burnt, undercooked, puffed up or dead flat.  I am not sure, in other words, that ‘leaven’ is an exclusive problem for Pharisees. I think you find bad leaven in any faith and any branch or flavour of it.  You can meet mild and accommodating fundamentalists; and zealous hard-line liberals.

As we all need leaven, and it is actually unavoidable (there is no good bread or wine without it), it is reasonable to infer that Jesus’ use of the word leaven with the Pharisees and Sadducees might imply some level of corruption. Care and caution should be exercised, however, in corruption as a qualifying term that is only to be found amongst the Pharisees and Sadducees.  Leaven was and is unavoidable, and used wisely and judiciously, powerfully good as a rising or fermenting agent. What could be so bad about the leaven of these Pharisees and Sadducees?

I think the answer may lie with making real bread.  There may be something inferred about the quality and quantity of leaven.  Bad leaven could result in a loaf that failed to rise.  It could make a sourdough loaf too sour.  It could make a loaf too crumbly and crumby.  Or too doughy and claggy, so difficult to chew and eat, and unpleasant to digest.  Too much or too little leaven in a loaf will lead to a loaf that is puffed up, and too fully of air pockets, or too dense and hard. 

The character of the local leaven itself is also an issue.  As with local yoghurt-making, some of the micro-cultures that continuously produce significant yields of natural homemade yoghurt were actually made (or begun) decades ago. Leaven, likewise, is not necessarily made fresh, and many-a-trusted ‘starter’ for sourdough loaves are derived from leaven that can have begun their life many years ago. So a corrupting leaven would continue to produce bad bread. There is something here, therefore, about the potential legacy of the leaven of the Pharisees and Sadducees.

So I think our best way of reading Jesus’ references to leaven are to imagine the outcomes after kneading and baking has taken place.  That returns us to the Flour Milling and Baking Research Association headquarters at Chorleywood. True, we aspire to catholicity and unity, but Christianity was never meant to be a religious version of the Chorleywood Bread Process – exactly the same loaf, tasting exactly the same, wherever you are.  (Yes, I know – the bread-making of the CBP has its mirror-image in the Alpha Courses of HTB. But mass-market faith has always had its appeal, and exercises like painting-by-numbers and joining-the-dots satisfy many-a-person. But do keep in mind that sales figures are not everything. Real Ale and Artisan Bread have their parallels in faith too).

Christianity, like theology, is local, and it must take on some of the distinctive character of its context in order to be faithful to the authentic calling to be incarnational – embodying Christ and loving the world in the time, space and place in which the gifts and fruits of the Holy Spirit are nurtured and developed to share with the world in gift and sacrificial service, and feed the body of Christ each and every week.  Put another way, just imagine Jesus saying: “pay attention to the Leaven of the Christians”.  What would that mean?

It would infer something about all the good things that Christian leaven can do: an agent for raising and lifting up; of blessing and feeding; of being sacrificially consumed in order to feed and nourish others; to be like Jesus, Bread for the World.  To be the “Leaven of Christians” might say something about legacy and heritage; it would have plenty to suggest about being distinctive, flavoursome and local – “this bread, here, tastes and smells beautiful, and how we wish we could take home the recipe”.  When we do so, of course, it never tastes quite the same, and can’t.  But it can taste different, end yes, even better that we remembered as we savoured.  The leaven has to be as natural as possible.  We have to trust that the bubbling and frothing come in their own time.  We don’t use pre-packed dry yeast.

Then again, perhaps the “Leaven of Christians” would be something to warn off others.  Christianity has its own pedigree that has drawn on the earlier leaven of the Pharisees and Sadducees.  As churches, we have excelled at narrow-minded bigotry and sectarianism.  We have been aloof and lofty, and taken condescension to new heights (or depths).  We have managed to talk about one bread, one body, one faith, one Lord – but then been racist, sexist, homophobic and classist.

Yes, we have plenty of bad leaven in our faith.  We have produced hard, stale inedible faith that only a few will bite on.  We have produced flaccid, flat sentimental piety.  Our leaven has also produced loaves that are so puffed up they appear to be enormous, only to find that once you try and tear of a hunk, it is all air.  It is best to beware of leaven.

Leslie Hunter was the Bishop of Sheffield from 1939-62, and in his The Seed and the Fruit (SCM, 1953, p.12), he offers this parable:

“As the threats of war and the cries of the dispossessed were sounding in our ears, humanity fell into an uneasy sleep.  In our sleep we dreamed that we entered the spacious store in which the gifts of God to humanity are kept, and addressed the angel behind the counter, saying: ‘We have run out of the fruits of the Spirit.  Can you restock us?’  When the angel seemed about to say ‘no’, we burst out: ‘In place of violence, terrorism, war, afflictions and injustice, lying and lust, we need love, joy, peace, integrity, discipline.  Without these we shall all be lost’.  And then the angel behind the counter replied, ‘We do not stock fruits here.  Only seeds…”.

For Seeds and fruit, perhaps, we should read Leaven and the Loaf?

Jesus might just as easily have said “you are the leaven of the dough” – just as he has invited Christians to be “the salt of the earth” in Matthew 5:13. Incorrectly, bible translations often render this saying of Jesus salt or seasoning for the world; but in fact Jesus speaks of earth as in soil, and the halas (Greek: salt) would have been dug out of the shoreline of the Dead Sea, as it was rich in minerals. The ancients used it in cosmetics, but most especially to nourish the ground, as it made excellent fertiliser.

Christians are therefore to be as fertiliser: dug into the ground to nourish the soil for seeds, growth and harvest.  We are invited to be a significant (if small) agent of transformative change in a much, much larger mass, that is only transformed by giving itself, sacrificially, to something bigger. Fertiliser, like leaven, does its work when it gets kneaded and worked in.  You can leave the spiritual-temporal chemistry to God.  Trust me on this, the Holy Spirit knows how to bake; just remember you are an essential ingredient in God’s recipe.  You are no good to anyone in a jar or a packet.   Christians need to get out more: we are not here to try and coax a few ever-wary people into our cupboards, containers and crocks.  We were always meant to be poured out. Liberally.

How will you and I be, like Christ, become Bread for the World? What is this leaven inside you raising up for the Kingdom of God?  How is Christ, in you, bringing about good “leverage” in the world: tipping things up and toppling some other things over, or lifting and levering some things up so others can reach up, over, under or beyond?  How are we, as Christ’s leaven, influencing the world around us for the common good?  How are we fermenting blessing, dissenting, resisting, rescuing and saving the world, and with gentleness, kindness, goodness, hopefulness, justice, peace and truth?   In what sense does our leaven not look like that of the Pharisees and Sadducees?  Can our work upon society by “invisible or powerful influence” be truly what Christ would be doing here, right now, in the places and spaces he has placed us?

How will you and I be part of Christ’s Bread for this World? How will this Leaven of Christ within us now feed the hungry, house the homeless, clothe the naked, and draw near to the prisoner?  How will we become the Body Language of God; the Verb of God; the Bread of Life for those who are hungry and ache and long for all the goodness that some good leaven can do?