Sourdough & Sake

sake shop

I have recently embarked on a new journey, making Sake. Something that I have been thinking about for several years, but had always considered to be too complicated for a non-Japanese speaker. However, two things changed my mind. One was the discovery of the excellent book Brewing Sake, Release the Toji Within by William G Auld, which demystifies the process enormously, and the other was discovering that at least one traditional Sake process uses the same microbiology as sourdough! And it is the latter discovery that leads to me including my first Sake brew in a blog on a sourdough website.

I won’t go into too many details on the history and production of Sake, there are plenty of other websites out there that do that already, but the important thing to note is that Sake is brewed like a beer rather than fermented like a wine. This is because unlike grapes, rice does not contain simple sugars that can be converted into alcohol by yeast, but contains starch, which must first be broken down into glucose and maltose by the action of enzymes. In the brewing of beer this is achieved by the action of malt amylases during the mashing process; in the brewing of Sake it is achieved by the action of amylases, enzymes produced by the fungus Aspergillus oryzae, otherwise known as the Koji-kin.

At a basic level, Sake is the product of two microorganisms, Aspergillus oryzae and Saccharomyces cerevisiae (brewer’s yeast) working in tandem. Whereas in grape fermentation all of the sugar is available at the start, in Sake fermentation the sugars are produced continuously by the action of the koji enzymes on the rice starch. It is this gradual provision of sugars that allows the yeast to operate at higher alcohol levels than are normally encountered in wine and beer making.

So where does the sourdough process come into this? Well, in the 14th century a group of Bodaisen Shoreki Ji Buddhist monks developed a Sake brewing process, called the Bodai moto, which started out with a mixture of polished rice, cooked rice and water that was left out in the open air to become ‘infected’ with lactobacilli and wild yeast. Once the rice starter had begun to ferment, the lactic acid-rich hooch, known as the soyashimizu, was poured off and used in the main mash along with the steamed rice and koji. The results depend on the fermentation of the mash with wild yeast and can be unpredictable, and the method died out around 1925. However towards the 1990s a group of brewers from Nara reintroduced the procedure, and had the soyashimizu introduced into the moto  rather than the main mash, relying on cultivated yeast to carry out the main fermentation.

Bringing your sourdough starter back to life

Frozen sourdough starter
Bringing a starter back to life can be a delicate operation

There will be times when you have to leave your beloved starter behind and either dehydrate it or banish it to the deep freeze. Neither process will harm it and I have successfully revived starters that have languished in the freezer for six months or more, or been dried for an equally long time.  The yeast and bacterial spores that are found in frozen/dried starter are pretty hardy but you will have to take extra care when activating your starter.

Whether your starter has been frozen or dehydrated give it plenty of time to acclimatise at room temperature before feeding it. The temptation will be to feed it as soon as it thaws out or rehydrates but this is not such a good idea. Here’s why. The population of micro-organisms that makes your starter unique was preserved by the act of freezing or drying so when you warm it up or rehydrate it it will be the same as before. However those yeast and bacteria cells are going to be a little jaded after spending time as spores and so whilst they may appreciate being fed, they would not appreciate the invasion of competing yeasts and bacteria that the feed will bring them! Normally this doesn’t matter as the active micro-organisms in the starter will easily out-compete and outnumber those arriving in the daily feed, but with a recently activated starter this isn’t a given, so do your starters a favour and let them recover for a few hours before giving them their first feed.

Preserving the character of a sourdough starter

Look after your sourdough starters and they will reward you
Look after your sourdough starters and they will reward you

There is much debate in sourdough circles about whether a sourdough culture or starter remains true to its origins once it moves into a new environment and much was (and still is) made of the age and provenance of the starter. I personally think that age can be discounted, because, assuming that the starter is fed on the same substrate (flour to most of us), after a certain period of time the micro-organisms in the starter will have stabilized. Each time you feed a starter with the same flour from the same source you are reintroducing the same yeast and LAB that the starter already has established. So since individual cells are very short lived, and will be replaced every day or so, it is the ratio of yeasts and LAB that determine the character of the starter and that is unlikely to change after a few months.

So, you have just acquired a 150 year old San Francisco starter, can you maintain its unique character, and if so, how? There are two ways to do this, one difficult and one relatively easy. The difficult way would be to order flour from the bakery where the starter came from and feed that to the starter every day. Kept on the same diet, and with the same micro-organisms being introduced each day, the starter would be expected to remain true to character. Although the starter will of course pick up fresh yeast and LAB from your kitchen, the numbers are going to be insignificant relative to the numbers present in the flour.

And the easy way? Well, if the starter is fed on sterilized flour and boiled water no fresh micro-organisms are going to make it into the starter in the first place, so whatever the original composition of the starter is, it won’t change! With this method you can maintain the character of any starter, simply by feeding the same type of flour but sterilizing it first. Flour can be sterilized by microwaving it for a few minutes on full power. Microwaving is an established method of sterilizing flour (Clin Lab Sci. 1999 May-Jun;12(3):156-60), it will not only heat up the flour by heating the residual moisture, but will heat up the yeasts and LAB disrupting their spores. Of course unless you are working in a completely sterile environment, some yeast and LAB are going to enter your starter, but these will be outnumbered by what is already there. If you want to test the hypothesis, try establishing a sourdough starter with microwaved flour and boiled water, you will have a long wait.

You may be wondering whether microwaved flour is still a viable feed for a sourdough starter, well it is. The microwaving process may denature some of the protein and affect the granulation of the starch but the essential carbohydrates utilized by the yeast and LAB remain unaffected. If you want to prove this quickly, just use the microwave-sterilized flour in a poolish and add baker’s yeast, it will soon become active.

I have put the theory to the test by rehydrating my basic white flour starter Audrey (this girl gets around) and feeding her sterilized maida (white wheat) flour here in Goa. After a bit of a sulk due to the high temperature she became active within 5 days and is doubling in volume every 12 hours. So the message is, yes, your 150 year old starter can be kept true to character, but you’ll need to put a little effort in to do it!

Creating a sourdough starter for Atta flour

Atta flour is an Indian wholemeal flour milled from durum wheat. Unlike regular wholemeal flour, it is finely milled so there are no bran flakes present, it is a pale yellow/brown colour. ‘Chakki atta’ is a traditional stone ground flour. Atta is used in India for traditional flat breads such as naan, puri and roti, but as it is a strong flour it can be used in baking leavened breads.

As I spend six months of the year in Goa the temptation to create a sourdough starter that combines the unique yeast and LAB of my Goan kitchen with that of the locally milled flour was too much to resist! If you have kept up to date with my trials and tribulations of creating an active starter in high temperatures you will know that sourdough starters behave quite differently once the temperature exceeds 30 C. To overcome the proliferation of LAB at the expense of yeasts, I took to allowing my starter to spend the night in an air conditioned bedroom which maintained a temperature of between 25 and 27 C, and those few degrees made all the difference. Now as winter approaches, the night time temperatures are falling below 27 C naturally and maintaining a starter is becoming much easier. Over the next five months the atta flour starter will stabilize and be added to the Sourdough Company family of speciality starters. As this starter really became active during the Hindu festival of Diwali on the eve of Lakshmi puja, I have decided that this starter will be named Lakshmi in honour of the Hindu goddess of prosperity. May all your bread be blessed!

Lakshmi
Lakshmi, the Hindu goddess of prosperity

Sourdough in the Tropics Part 3

Sourdough starters can behave unpredictable in the tropics
Sourdough starters can behave unpredictable in the tropics

Now that my starter is fully active I have started a regime of twice daily feeds and made sure it stays in a relatively cool environment day and night. I have been rewarded by seeing it double in volume after each feed and produce some wonderful bread. I am using 80% atta flour (fine ground wholemeal) 20% maida flour (a refined softer wheat flour) with a hydration of between 65% and 72% depending on whether I use my bread maker or bake in the oven. As I could not bring my trusty Cloche out with me, oven baking is not as easy as in the UK so I use the machine more.

Over the next six months the atta starter will stabilize and become a part of my sourdough family, I just need to decide on a name now!

 

 

Sourdough in the Tropics Part 2

Sourdough starter
Offering sourdough starter to Buddha…

After my initial excitement of seeing bubbles forming in my starter so quickly things took a turn for the worse and the starter stopped. I fed it every six hours but apart from a few bubbles on the surface, not a lot was happening. It smelled ‘correct’, that sweet/sour sourdough odour was there, but not much sign of yeast activity. Time for some research. After a short while I discovered the work of Michael G. Gänzle, a researcher who published a paper (Modelling of Growth of Lactobacillus sanfranciscensis and Candida milleri in Response to Process Parameters of Sourdough Fermentation; Appl Environ Microbiol. 1998 Jul; 64(7): 2616–2623) which is essential reading for the sourdough geek. To summarise his findings, LAB performs better at higher temperatures than yeast.

Reproduction Rates of LABs and Yeast L/Y 
T(°F) T (°C) L. SF I L. SF II Yeast Ratio
     36        2 0.019 0.016 0.005 3.787
     46        8 0.047 0.043 0.021 2.222
     61      16 0.144 0.150 0.114 1.265
     68      20 0.239 0.259 0.225 1.064
     72      22 0.301 0.332 0.295 1.021
     75      24 0.374 0.416 0.365 1.024
     82      28 0.535 0.598 0.417 1.284
     86      30 0.609 0.672 0.346 1.760
     90      32 0.658 0.706 0.202 3.255

Between 20 and 26O C, yeasts are in control, above this temperature the LAB becomes dominant. What does this mean for the sourdough starter at higher temperatures? It means that a starter will form but the ratio of LAB to yeast will favour the LAB, so lots of sour flavour but little or no COto make the dough rise! So that evening the starter accompanied me into my air conditioned bedroom and spent the night at a relatively cool 26O C. Come the morning the starter was full of bubbles and although not doubled in volume, was showing signs of activity. Quite a revelation, fascinating in fact, but what to do about making my bread rise? Being pragmatic (and needing bread) I decided I will mix some of the LAB-heavy starter with a regular yeast poolish and use this as a leavening agent.

Although I am against ‘Sourdough lite’, or the trick some supermarkets have of adding a dash of starter to yeast-leavened bread in order to call it sourdough and charge more, I had to do just this when my starter wouldn’t perform. To summarise the problem, high temperatures were causing a proliferation of LAB at the expense of the yeasts in the starter. So lots of flavour but not a lot of leavening! To work around this I problem I made a poolish in the normal way and left it overnight to become fully active, then mixed this with some starter and made up some dough. Result, a fully risen, flavoursome loaf of bread!

Sourdough in the Tropics Part 1

2015-10-21 14.44.18

I spend my winters in Goa where the daytime average temperature hovers around 30C and the humidity rarely drops below 70%, ideal conditions for creating a sourdough starter you would think. A year ago I came to Goa full of optimism, my first starter back in the UK had taken less than a week to become fully active so I had high hopes for my efforts in Goa. I mixed up a starter of the local atta flour (stone-ground fine wholemeal) and water put it in a jar and waited, and waited… Nothing seemed to be happening, there was a little ‘hooch’ on the surface every day but no signs of activity. Days passed and I fed the starter every 24 hours, just as I had back in the UK, but I never once saw a bubble. In the end I went back to using fresh baker’s yeast (of which there is a plentiful supply in Goa) to make a poolish and used that for leavening my bread.  I couldn’t understand it! Local friends with bakeries were producing sourdough bread quite successfully and spoke about how perfect the conditions were for their starters. It took me quite a while to work out why my attempts at raising a starter might be unsuccessful, perhaps it wasn’t that the starter wasn’t working it was that it was working too quickly! Yeasts double in activity for every 10C, so a starter in Goa will be working twice as quickly as one raised in the UK. I had fed my starter in the afternoon and by the next morning when I examined it, it would have already gone through an entire cycle of doubling in volume and then exhausting its feed.

A year later, I’m back in sunny Goa and one of the first things I did was to mix up atta flour and water and get my starter going. The mixture was placed in a jar mid-afternoon with an ambient temperature of 30C and 66% relative humidity. I checked on it again at 10 pm (30C / 70% RH)  and saw a few bubbles in the mixture so I fed it again with another equal measure of flour and water. I checked it again first thing in the morning (27C / 75% RH) and it was actively bubbling away, 18 hours after setting it up! So I will keep feeding for the next 4 or 5 days before setting to work on producing its first loaf, watch this space.

In praise of the bread maker

Panasonic SD255It is a fact that were it not for the Panasonic SD-255 I would not be baking bread now. I  had always considered bread making to be fiddly, messy and time-consuming until I visited a friend in Brighton some years ago. I watched as he casually weighed out different flours, threw the ingredients into the bread maker and set the timer. I awoke in the morning to the smell of fresh bread wafting up the stairs and discovered a warm and tasty loaf waiting in the kitchen. How easy was that? As a fellow geek, I knew that when he recommended the Panasonic he had done all the research and that would be the best available on the market. When I mentioned that I was about to invest in a bread maker I discovered that several friends had this very model lurking in the back of cupboards unloved and no longer used! So I began baking on an almost daily basis, in the early days I used yeast and it was about a year later that I started to experiment with sourdough starters. The early experiments did not produce great results; the SD-255 was a versatile machine, but it was made before sourdough took off and had no special programme for this type of bread. But Google was my friend and I learned two things; use the longest programme available and use a larger amount of starter than you would when making sourdough by hand. So in the case of the SD255 this meant using the French bread programme (six hours). Once I had perfected my starter, feeding and timing it right to ensure maximum activity, I was able to use the normal programmes for the type of bread I was making and get perfect results every time.

Sourdough bread
Sourdough bread made in a bread machine

Meanwhile my baking friends had graduated to mixing their dough with stand mixers and their talk was of banettons and baking stones. I was assured that once I started making bread by hand I would never go back to my bread machine again. I resisted for six months, then I bought my first banetton (note that I said ‘first’). The SD255 was still used to knead the dough (I was still reluctant to get my hands messy) but then it was rested, proved, retarded, shaped, scored and baked by hand. I haven’t looked back really, I still love my machine and if I run out of time or I am feeling lazy, I will still pop the ingredients in overnight and wake up to the smell of freshly baked bread.

Now a friend has ordered the latest Panasonic bread maker, the SD-2511B – which has a sourdough programme, and I am supposed to be taking it back to Goa for her. I wonder if she will notice if I substitute my old one…

Gluten-free sourdough starters

gluten-freeGluten is getting a lot of bad press at the moment and as gluten is what makes traditional wheat-based dough elastic and extensible, this presents a basic problem for the gluten-free baker. When I first started baking bread (using a machine) in India I found the local flour to be deficient in gluten and asked my wife if she could find gluten powder in the local health food shop. She claims the reaction from the owner was as if she had asked for a tub of whale blubber…

But I won’t enter the debate on how bad gluten may or may not be for people who are not coeliac sufferers, suffice it to say that there is a considerable market for gluten-free products and this determined the direction for the next family of starters. Gluten-free flour is a mixture of non-wheat flours. Wholemeal gluten-free flours include: brown rice flour, buckwheat flour, corn flour, mesquite flour, millet flour, oat flour, quinoa flour, sorghum flour and sweet potato flour. White gluten-free flours include: arrowroot flour, cornstarch, potato flour, potato starch, sweet rice flour, tapioca flour and white rice flour. Assuming that you don’t have a nut allergy, you can also include nut and bean flours such as almond flour, chestnut flour, coconut flour, hazelnut flour, fava bean flour, garbanzo bean flour and kinako bean flour.

Gluten-free sourdough starter
Gluten-free starters are usually very active

For our starters we decided to use a branded flour that our customers would recognise and feel confident in using, and we chose Doves Farm gluten-free white and brown bread flours. The gluten-free brown is a mixture of rice, potato, buckwheat, carob and tapioca flours with sugar beet fibre and xanthan gum. The gluten-free white is a mixture of rice, potato and tapioca flours with xanthan gum. Both of these produced a very active starter within a few days of commencing feeding. Their consistency differs from that of wheat flour-based starters and is typically less smooth. Because of its different structure, a gluten-free starter can often appear like a honeycomb with distinct bubbles trapped in its flour matrix (see diagram).

 

Introducing – Bacchus sourdough starter

Bacchus was the Roman god of wine
Bacchus was the Roman god of wine

Flush with success from our first ventures into the world of sourdough (Audrey) we were keen to experiment with different starters. There is much debate on whether starters made with different flours or starters grown in different environments produce different results. As we are committed to the scientific method, we decided to find out for ourselves! We were starting to incorporate spelt flour into our baking so the first experiment was a starter based on wholemeal spelt flour. We had also read about the effects of any wild yeast present in the initial liquid used in making the starter so we incorporated yeast growing on the skins of the Bacchus grapes growing on vines planted in our garden. Spelt flour was popular for making bread in Roman times and Bacchus was the god of wine and agriculture so Bacchus was the name given to our next starter.

Bacchus grapes
Bacchus grapes are prone to mildew

Unfortunately our success with Audrey wasn’t repeated, and the new starter refused to get going. Over a week went by and there was no sign of activity, what had gone wrong? We tried everything, increasing the temperature and frequency of feeding had no effect, what to do? This is where I learned a very important lesson, which seems so obvious in hindsight that I am almost ashamed to write it down. Bacchus vines suffer from powdery mildew and to prevent this they get sprayed with fungicide early in their growth cycle. I hadn’t checked when the last spraying had occurred and since yeasts are fungi, they were effectively eliminated from the grape skins by this treatment! So it was back to the beginning with Bacchus, after checking the pre-harvest intervals had elapsed we prepared another starter. What a difference, it was almost as if the starter wanted to make up for lost time! Within a week we had a very active starter bubbling away in competition with Audrey.