I am an accredited beer sommelier and the founder of the School of Booze. Whenever I’m educating about beer one of the questions I am most often asked is ‘What is the difference between ale and lager’. The answer gives me the opportunity to talk about The Family Tree of Beer. This is how I explain it. Picture a Venn diagram. Each of the three interlocking circles contains one of the following words: Ale, Lager, Wild Fermentation. Each is a branch of the family tree of beer. Where the circles overlap, the headline is BEER. Each branch contains sub-branches, which represent the various beer styles. Ale includes IPA, Barley Wine, Mild, Porter, Weizen and dozens of others. Lager incorporates Helles, Pilsner, Märzen, Schwartzbier, Bock and several more. Wild fermentation comprises Lambic, Faro, Gueuze (three Belgian styles) and others, all of them acidic and sour and often mistaken in blind tasting for cider or wine. Only a handful of British brewers produce wild fermentation beers – most of them are ale and lager brewers. What Determines The Branch That Beers Sit On? The main factor is the strain of yeast used in fermentation. Ale brewers employ a strain of cultured yeast known as Saccharamyces Cerevisiae which ferments quickly at temperatures between 16-20 ̊ C (60-68 ̊F) adding fruity aromas and flavours known as esters to the beer. It is often referred to as warm fermenting or a top fermenting (denoting the direction the yeast cells head in the fermentation vessels). Lager brewers used a strain of cultured yeast called Saccharomyces Pastorianus often referred to as a bottom fermenting (denoting the direction the yeast cells head in the fermentation vessels) or cool fermenting yeast which ferments slowly at lower temperatures than ale yeast - between 10-15 ̊ C (50-59 ̊F) and confers a crisp body to the beer by fermenting one of the sugars (melibiose) that ale yeast does not. Lager yeast produces fewer esters than ale yeast and so lagers are often described as ‘clean’ to drink. Wild Fermentation brewers do not use cultured yeasts, instead they encourage untamed non-conformist wild yeast spores, such as a strain called Brettanomyces (also known as Brett), that float in the air or that colonise wooden beams or beer barrels in the brewery. They also rely on wild microbes such as Pediococcus and Lactobacillus. The aromas and flavours bestowed by the yeast and microflora are unpredictable and complex and include sourness. But to confuse the issue there are mixed fermentation beers such as Flanders Red Ale and Oud Bruin (another Flanders speciality) which are fermented with ale yeast and then aged in oak barrels where wild microflora imbue sourness. And beers described as kettle sours or fruited sours are fermented with ale yeast and then lactic bacteria is added during the brew for the characteristic tang. The Importance of Water’s Mineral Composition With ale and lager the mineral content of the brewing water is also a factor. A glass of beer is composed of up to 95% water. The chemical composition of water is one of the factors that determines which branch the beer styles belong to. Look around the world and note what the heritage style of beer is brewed in that area and you can make a guess about the mineral content of the water. For instance, historically Burton on Trent in the Midlands was celebrated for India Pale Ale (IPA) and the reason is river Trent water is high in calcium sulphate which makes the best IPA. River Thames water is high in calcium carbonate and London was renowned for Porter and dark Stout beers. In ales, the water is high in mineral salts and the type of salt is influential. Water high in calcium chloride is good for making sweeter beers such as Mild. Water with high levels of calcium sulphate and bicarbonates is perfect for dry beers such as India Pale Ale and it also enhances hop aromas and flavours. Water high in calcium bicarbonate is used to make dark Stout. Water low in mineral salts is ideal for lagers such as Pilsner - this showcases the sharp bitterness of hops and the sweet biscuit of the malts. The presence or absence of mineral salts makes a difference to the body of the beer. Brewers can treat the brewing water by adding or subtracting minerals. Ales tend to be fuller bodied than lagers, which have a lighter body and crisp texture. Many brewers I know studied chemical engineering or biochemistry at university and understand the complicated science of brewing. For readers who are not biologists or chemists my explanations of yeast and water are simplistic accounts but are intended to be straightforward and easy to understand. Cheers! ***** Jane Peyton is the drinks ambassador for Love British Food and is the founder of the School of Booze and author of several books including The Philosophy of Beer – signed copies here .

‘We are what we eat, so eat something natural’ is one of my mantras. So when you consume an alternative product made from a variety of unknown ingredients such as a ‘plant-based’ cheese pretending to be a Brie or a Camembert, or a product acting like a chicken (which is very much like halloumi). It. Doesn’t. Work. Vegan food mimicking the real deal does not cut it for me. The plant-based ‘bacon’ is far too uniform in its appearance (it looks like a zebra crossing on the plate) and ‘perfect’ in it’s execution; it doesn’t have the natural fat oozing out of the meat, there are no streaks of splendid peccadillo colours, and the flavour is bland at best. So why are we judging plant-based food on how close it can be to natural animal products? They’re completely different and the vegan or ‘plant-based’ alternative cannot come close. It’s like judging Jane Austin to a Charles Dickins novel; they’re both still art and creative in their own right but completely different. The former doesn’t try to emulate the other, or indeed fall beneath its other shadow, the novel just celebrates its own creativity upon its own merit and this is what vegan and plant-based food can and should do too. Highlight the importance and significant diffidence of plants but please leave the cheese and bacon aspirations to the sheep, cows, goats and pigs. I thoroughly believe that vegan and plant-based food can shine and provide a balanced alternative and/or supplementary diet with a beautiful and sustainable homage to our plant life. Please let us celebrate plant-based food; harvest the produce and make products that allow the plants to shine and make them the star of the show, (as well as all the animals). There’s room in the world for plenty more stars and our plants deserve it. The therapeutic, medicinal and nutritional power of plants cannot be overestimated. They are, after all, the source of what gives us life! The carbon cycle illustrates how we can all live together in a harmonious and productive way. Plants on land and in the ocean convert carbon dioxide to biomass through photosynthesis. The carbon returns to the atmosphere when the plants decay, are eaten and digested by animals. I think there is so much beauty in nature’s simplicity and wonder, and we often learn so much from Mother Nature. Aren’t we lucky to be living in a country where we have so much produce and can enjoy the luxury of this vast choice to satisfy all of our individual diets and preferences? Meat, dairy, fish, seafood, vegetables, cereals, chillis, beer, wine, culinary lavender, edible flowers, sugar, honey, herbs and so much more! Whatever diet you choose to live by – whether you are vegetarian, pescatarian, vegan, omnivore, flexitarian – aren’t we lucky that we have this luxury of choice when other people in the world are not so fortunate? Consuming ‘better’ meat, is perhaps only desirable and achievable for possibly the most affluent demographic of our society? The good and philanthropic intentions are there, but in practice, I personally don’t think this is realistic or indeed achievable. We conveniently forget that there are currently 8.4 million people in the UK who are living in poverty which is the equivalent of the population of london. Insisting that we should get the best quality meat that money can buy is a little ignorant and patronising. However, Great Britain does have the best animal welfare standards in the world, and for those who can afford the luxury of choice, we can, and should, be eating 100% pasture-fed livestock. Please don’t eat lamb from New Zealand of beef from Australia, but please do support our British food producers; especially our farmers. The provenance of our food is of the upmost importance and crucial to the education of our children. Simply knowing where our food comes from lends each and everyone of us a deeper understanding of the world, nature and the circle of life. Whether or not you live in the town or in the country, coast or inland, bridging that gap is what I help try to do. To understand and appreciate our food, we need to know how it’s produced I believe wholeheartedly that we, as a nation, need to support our British food producers now more than ever before and to ensure we educate and communicate to the general public the right information, especially about regenerative agriculture, and sustainable fishing, and not incomplete, sensationalist propaganda. This is so people can make informed decisions and choices that’s good and right for them. So with more plants, and better meat, we need to support our farmers, because without them there is simply no food. My other mantra is to ‘buy local, buy sustainably, buy seasonally, and when you’re in this country, please buy, and love British food’. Follow @jennyljefferies

As a Stakeholder and supporter of Love British Food, The Sustainable Restaurant Association shares insights into why the provenance of our food matters and how restaurants can celebrate the best of British food.