Cebiche / Ceviche / Sebiche / Seviche

Added on by Josh Evans.

posted by Sebastian Moreno Henao

As a Latin American, cebiches are very familiar to me. There are many varieties, from México to Chile, across Honduras, Guatemala, Ecuador, Colombia, Peru, and many other places as well.

It is the same with its etymology. A lot of theories have been proposed. One of them says it comes from a Spanish word: “cebo” which means “bait”, probably because of its similarity to chopped fish. Another proposes it comes from the word “escabeche”, which itself comes from an Arabic-Spanish word: “sukkabak” , a method to preserve meat in vinegar. And a third suggests that it comes from a Quechua (indigenous language from some South American tribes) word: “swichi” which means ‘fresh fish’ or ‘tender fish’. It is also due to these different etymology that one can find so many variations in the spelling.

The many forms of this traditional dish share one common trait, which is how acids can transform the proteins in food without applying any source of heat, and in a short period of time. We were interested in playing with this principle with other techniques and ingredients we use, such as vinegars, kombucha, curing, and infused oils.

an early trial with rhubarb vinegar on different insects

an early trial with rhubarb vinegar on different insects

In cebiches, everything is about pH. Proteins change because of acid – the introduction of new hydrogen atoms disrupts the hydrogen bonding within and between amino acid chains. Acids thus denature the proteins’ quaternary and tertiary structures (the specific shapes that emerge as a result of hydrogen and other bonds), leaving them in loose strands and allowing them to reconfigure in new ways. This is the mechanism that transforms the texture of protein-rich food.

For our acids, we used 4 different vinegars: strawberry, rhubarb, cucumber, and beer. Additionally we made two novel acids by fusing chicha and kombucha. Chicha is a traditional Latin fermented beverage from Central America and the northern part of South America made from corn; the resulting chicha kombuchas were surprisingly nice.

black corn to be turned into chicha

black corn to be turned into chicha

To go with our different acids, we chose five different types of proteins: the traditional fish and shellfish, always used in Latin cebiches; red meat, very common, which we lightly cured to make it a bit more interesting; and two more rare ingredients if we speak about cebiches: insects and legumes. So here they are, the chosen ones: mackerel, razor clams, beef loin, green peas, and bee larvae.

We also made some different oils and salts as seasonings, with products like lemon thyme, lemon verbena, berries, and roasted koji (yes, koji - what a surprise!).

an early version of the bee larvae ceviche

an early version of the bee larvae ceviche

The results were very intriguing. Timing is one of the most important aspects of this technique: the longer the protein is in contact with vinegar, the more dramatic the change on its ‘cookedness’ will be – even within a range of a couple minutes. We saw this happen in many ways.

First, the most close to tradition. The razor clams were marinated in cucumber vinegar for 7 minutes, together with some sugar kelp and søl and dressed with lemon verbena oil and salt. The razor clam was excellent with a good firm texture, while the seaweeds were gummy and didn’t add to the dish, so we removed them in later versions.

The mackerel was put into a strawberry vinegar also for 7 minutes, with cranberry oil, lemon verbena leaves and mackerel skins.

The meat, as I told you before, was cured – with salt and brown sugar, to balance the tastes while still optimizing the drawing out of water from the flesh. We used stronger seasonings for this one: beer vinegar (for about 10 minutes), roasted koji oil and clove root. We didn’t need to put more salt because of the cure.

The peas we marinated in the chicha-kombucha for 24 hours and their colour, flavour and texture changed completely. We dressed them with quince oil and some raw peas to make a contrast with other flavours. But in the end, we decided to dress them simply to show the unique crisp yet soft texture of the ‘cooked peas’ on their own.

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The bee larvae gained a slightly firmer external layer through contact with the vinegar, while retaining their creamy center, almost like a spherification; but if we let them stay more than just 3 minutes in the vinegar, the layer became thicker and thicker and the larvae became less creamy and nice to eat.

It was interesting to see how the different types of protein responded to the different acids, giving pretty diverse results from the same process. Overall, a very versatile technique that we can use on different ingredients around the world.

Plus, the mise en place was great. 

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Here’s a recipe for our favourite.

Bee Larvae Cebiche

Bee Larvae                                  15 g
Rhubarb Vinegar                         100 ml
Lemon Thyme                              3 g
Freeze-dried Lingonberries          5 g
Red Oxalis Stems                         3 g
Søl Salt                                         5 g

Pick lemon thyme leaves and chop dried lingon-berries and oxalis stems very finely.
Pull the bee larvae from the freezer and defrost for 3 minutes. Add them to the vinegar and season with salt. Wait another 3 minutes.
Take the bee larvae out from the vinegar and dress them with the other ingredients (stems, lingon-berries and lemon thyme).
Enjoy a delicious bee larvae cebiche!

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References 

"Diccionario Panhispánico de Dudas.  " Real Academia Española . <http://lema.rae.es/>. 10.2005. 18.7.2013

Katz, Sandor E. The Art of Fermentation. USA: Chelsea Green, 2012.

Multiple. "Cebiche". Wikipedia . <https://es.wikipedia.org/wiki/Cebiche>. 7.7.2013.

Unknown. "Cuál es el origen de la palabra 'Ceviche'?". Planeta curioso . <http://www.planetacurioso.com/2007/07/20/cual-es-el-origen-de-la-palabra-ceviche/>. 20.7.2007. 7.7.2013.

annette1402. "Etimologia Del Ceviche". Buenas tareas . <http://www.buenastareas.com/ensayos/Etimologia-Del-Ceviche/2545655.html>. 07.2011. 7.7.2013.

 

Koji-chovy

Added on by Ben Reade.

posted by Ben Reade

I need to admit to an obsession: Basque salted anchovies. In 2010 I was lucky enough to see them being produced in the tiny Basque fishing port of Bermeo. The painstaking effort taken over each little fish produces a remarkable product. Let me explain the process.

Very fresh anchovies are layered in barrels with salt. Nobody will tell you exactly how much salt, but it's around 10-20% of the weight of the fish.  They are then left there for at least a year. During this time, osmosis draws water out of the fish until they are sitting in their own brine and equilibrium of salt concentration is attained. This causes the flesh to firm up and endogenous enzymes (hydrolases, proteases, nucleases, glycosidases, aryl sulfatases, lipases, phosphor-lipases [1] ) combine for autolysis of the flesh. The breakdown of the flesh is further facilitated by the enzymes in the anchovy's gastrointestinal tract – which is of course specifically designed for breaking down fish – to give it the rich umami taste typical of an easily digested protein.

After a minimum of one year, the anchovies are removed from the brine, and all by hand they are filleted, the skin is scraped off, and they are cleaned and trimmed. The polished fillets are then lined up on a clean towel, and rolled up.  The rolled-up towel is  put into a centrifuge which is spun to pull the water from the flesh. Selected by size, shape and quality, they are placed one by one into tins or jars, where they are covered in neutral oil. It was wonderful to watch these old ladies processing each delicious fillet with such care.

A Basque lady places anchovy fillets into tins (2010, Bermeo)

A Basque lady places anchovy fillets into tins (2010, Bermeo)

Although anchovies occasionally swim as far north as southern Scandinavia, they are not fished in any commercial quantity. But I wanted to make some kind of Nordic equivalent – what to do? The answer came like a rainstorm of fish – HERRING. There is a long history of salting herring for preservation in Scandinavia – but I wanted to end up with a product similar to that Basque fillet I had grown to know and love.

But there were problems. The best anchovies are cured with their entrails intact, so as to provide enzymes which facilitate the hydrolysis of the flesh from the inside out; but herring is a thicker fish than anchovy, which means it takes too long for the salt to permeate the guts and keep them fresh. So, the guts had come out, but when the guts come out, sadly so do their enzymes. Yet after reflecting on some of the lab's earlier work on umami arising from salt rich fermentations, it became clear that I could in some way replace the endogenous enzyme activity of the guts with exogenous enzyme activity from koji. And so was born the Koji-chovy. 

 

Curing koji-chovies, photo by Claes Bech Poulsen

Curing koji-chovies, photo by Claes Bech Poulsen

Herring Koji-chovies 

Now, take your herring, remove the head by breaking the neck backwards, and cleanly remove it with as much of the guts as possible. Leave the mandibular bone (or whatever it's called) to give the fish a good clean look. Make some barely koji (some pretty good instructions can be found here) and then follow this recipe:

2000g Aspergillus oryzae Koji of Pearled Barley

6660g Headless, gutless Herring (10kg whole weight)

1970g Salt

Mix 100g salt with the koji, and then stuff the fish with the koji, layering the stuffed fish with salt in between the layers.

Weigh the fish down and leave them at 2 °C until they are submerged in their own brine. Keeping the weight on top, leave them at ambient temperature for 1 year – although I impatiently started experimenting already after 6 months.
When you're ready to move to the next stage, fillet, debone, dry and cover in oil, or of course you can also marinate them. A successful marinade to try is a sprinkle of powdered juniper berries, crushed lingon berries and a dash of aged apple vinegar with some neutral oil. Vacuum seal them, and leave a couple of weeks to infuse.

So. To put things simply, these are bloody delicious, if a little bit salty. The saltiness is pretty easy to tackle, in the old Finnish method of leaving them to soak in milk overnight before grilling, but anyway, anchovies are salty and should be salty and our experimentation doesn’t stop here.

After the initial success of these prototypes my mind wouldn’t stop and we had to take the project further. This called for some of microbe friends to get involved. So I was able to lay my hands on two pretty special strains of bacteria, Tetragenococcus halophilus and T. muriaticus. The T. halophilus has been isolated from (get ready to gasp) Basque anchovies, and the T. muriaticus from a Japanese ferment called Shottsuru, a salt-rich ferment of squid liver. Tetragenococcus spp. are halophilic lactic acid bacteria which requires NaCl for growth and is tolerant of salt concentrations up to around 20%. At first, T. halophilus was the only species under the genus Tetragenococcus, yet T. muriaticus was proposed as a new species under the genus in 1997 [2]. Anyway, we have them both in the lab and are indebted to Eddy Smid, our fermentation and biotech guru at Wageningen University for sending us these fantastic and hard-to-find microbes. We now have these different versions slowly fermenting away downstairs, with our two cultivated strains of microbe, as well as wild ones for a control - we will see in time which emerges the winner.

And boy do we have a treat for the winning microbe. In March we were given this beautiful amphora by the talented potter Aage Würtz. My aim since first conceiving this pot is to pick a very successful ferment to inoculate the pot, so that the microbes can harbour their populations in the pourous ceramic walls and be forever perpetuated in the pot’s contents.

May this be a long and fruitful journey, and may herring continue to flourish in our oceans! 

 

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1. Peter E. (ed) (1998) ‘Fish drying & smoking: production and quality’ Technomic Publishing USA.

2. Satomi et al (1997) 'Tetragenococcus muriaticus sp. nov., a new moderately halophilic lactic acid bacterium isolates from fermented squid liver sauce’ International Journal of Systematic Bacteriology p. 832-836

Birch SAP – a seasonally active pulse

Added on by Ana Caballero.

posted by Ana Caballero

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Trees absorb water and nutrients through their roots from the soil. The water is passively conducted upward by xylem vessels to the leaves, where photosynthesis converts carbon dioxide into sugars. After this transformation, the sugar-rich water is distributed through the phloem to all sites of growth: buds, branches, blooms, roots, and fruits. This medium of circulation in higher plants is known as sap. [1]

Due to the success of its syrup industry, the sap most people are acquainted with is that of maple trees (Aceraceae) growing mainly in Northern America. In Eurasia, although of significantly less economic impact, the predominant sap comes from birch trees (Betulaceae family)The only part of this continental mass where birch sap has been gathered industrially was within the Soviet Union. Its transformation for various cosmetic, medicinal and edible uses was relevant to the soviet economic system. Hence, much of the research on production technology and properties of this sap has been published in Russian. This fact, along with the large birch stands and low population density is the reason why Russia, Ukraine, Belarus, Estonia, Latvia and Lithuania are the only remaining counties where sap collection remains an important activity. [2]

In Norway birch sap has been used mainly as a fresh drink, but in some areas it is transformed into a kind of wine. In Sweden it has been used for gruel (adding barley meal) and in some areas made into ale by mixing with malt and yeast. During the last real famine in Sweden in 1867, tree sap was widely used in the southern areas and was referred to as the "poor-man's cow". Birch sap has also been used among the Saami in Sweden, especially among the Forest Saami in Västerbotten. Wine from birch sap is nowadays made by some home producers, the most well-known being the “Grythyttan Björkvin”, a sparkling birch wine  developed from an old recipe from 1785. [2]

In Finland various techniques have been used used to collect the sap. In certain areas it was also gathered by digging pits into the birch tree stumps and allowing the sap to accumulate. It was widely used both by the peasantry and the nobility and has also been recorded in the use of wines and beer. [2]

In Denmark, birch sap has been recorded to have been used for making ale and added to cheese to protect it from vermin. it was included in the 'Danish pharmacopeia' recommended to treat rash, intestinal worms and scurvy. [2]

Many other uses throughout the region include the production of vinegars, boiled into syrup, refined into sugar, and added in coffee. Used as well against anemia, cancer, tuberculosis, kidney and liver stones, gout, arthritis, rheumatism, cold, and skin diseases, birch sap, like many traditional foods, has carried both gastronomic and medicinal roles. [2]

There are many other tree taxa recorded for the use of their sap – for example, the sap and inner bark from pine (Pinus Sylvestris L.) and spruce (Picea abies L.) were used by the Saami people by drying it into flour, and mixing with milk and fat. Other saps used throughout Eurasia include ash (Fraxinus excelsior L.), sycamore (Acer pseudoplatanus), beech (Fagus sylvatica L.), hornbeam (Carpinus betulus), Turkey oak (Quercus cerris L.), Wych elm (Ulmus glabra Huds.), and Eld elm (Ulmus minor Mill.). [2]

The knowledge surrounding the diverse uses of tree saps has been dwindling, but in some European countries, the use of sap  is being revitalized. Arborist Tage Rønne is a leader of the front in Denmark. During the spring he is a sort of seasonal forest farmer, harvesting the sap and delivering it fresh the same day. After one of his deliveries to the Lab, a group of us decided to pay a visit to his birch grove and learn more about the process.

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Birch trees, along with beech and oak, represent an approximate 43% of Danish forests [3]. For tapping sap the main species used in Denmark are Silver birch (Betula pendula ) and European White birch (B. pubescens ). The sap run in the spring is the result of the plant releasing its stores to nourish the newly developing buds.

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Fresh sap has a certain enigmatic character to it, sterile yet vibrant with a hint of mysticism. Its crystal clarity gives it this sense of eternalness... and it can be deceiving how ephemeral in fact it really is. At room temperature, it lasts only around 48 hours. It can be frozen but in the past when this was not an option, the way of letting it live beyond its season was, like with many raw materials, through transformation. As the ethnobotanical information above demonstrates, syrup was not the sole purpose for birch sap; the sap's sugar content was valued even more for its potential to be fermented.

Table adapted from reference  [2]

Table adapted from reference  [2]

At the Lab, our interest in exploring the potential of tree saps for fermentation has just begun. Birch sap kombucha was our choice this season. Although there is much to explore with its traditional uses, this was an opportune time to follow up on our Kombucha experiments from December last year. This idea came from chef Jonnie Boer of restaurant De Librije who has been experimenting successfully with tree saps for some time. 

When transforming this liquid, the closest reference commonly available is maple sap. It is important to note that its chemical composition and sensory properties differ clearly from those of birch sap:

- In maple syrup the dominant sugar is sucrose, while in birch it is mainly glucose and fructose (invert sugars). Because sucrose accounts for only a fraction of the total sugars in birch syrup, finished birch syrup can be concentrated to more than 66-66.5° Brix, which is the fixed level in maple syrup [4].

- The acids in birch sap are malic, phosphoric, succinic, citric and fumaric. The most predominant is malic acid (as well for maple) which mainly characterizes the acidity within the sap.              

- Birch sap has a varying but moderately low pH. A study that monitored the pH of a sap flow over the season recorded the following: in the beginning of the flow season, pH was slightly higher than 7.5, decreasing to around 6.0 within two weeks. The lowest values, 5.3-5.5, were reached at the end of April and in the beginning of May. This demonstrated that birch sap has no standard acid composition, but rather its composition fluctuates and does not necessarily follow a standard pattern [5].

- The acids alone do not determine the acidic taste, nor do sugars the sweetness; it is the ratio of both that define our perception. 

Tree saps offer a host of opportunities to conduct further research, especially when it comes to their gastronomy. Just as wild herbs are being explored by more and more people, we hope there will also be an increasing interest in the chemical composition, toxicology, and sensory qualities not only of saps but of the many other components of these large vascular plants that, more than just part of the scenery, are a remarkable culinary subject unto themselves. 

 

REFERENCES

1.    Kundt, W. and Gruber, E. The Water Circuit of the Plants, Do Plants have Hearts? 2006, Institut f¨ur Astrophysik der Universit¨at Bonn, Auf dem H¨ugel 71, D-53121.

2.    Svanberg, I. et al. Uses of tree saps in northern and eastern parts of Europe. 2012, Polish Botanical Society, 81(4): 343–357.

3.    Nielsen, M. The Danish forest sector, World Forest Institute.

4.    Kallio, H. et al. Composition and Properties of Birch Syrup (Betula pubescens). 1989, Journal of Food Chemestry 37, 51-54.

5.    Kallio, H. and Ahtonen, S. Seasonal Variations of the Acids in Birch Sap. 1987, Journal of Food Chemestry 25 (1987) 285-292.