Food Ways: Sea biscuits


OLDEST SHIP BISCUIT. This specimen appears at the Maritime Museum in Kronborg Castle, Elsinore, Denmark. The biscuit dates from 1852. Image: Paul A. Cziko (

It has been an interesting journey doing the research on sea biscuits and I am sure there is more information I haven’t found doing a quick internet search. Sea biscuits are the Navy’s equivalent of hardtack, which is a relatively new comer as it was named by the 19th Century American army. Given the simple recipe (mix flour and salt with water to make a dough, roll out into patties, bake in a medium oven for 30 min at least twice) these biscuits were probably around in prehistoric times and still surviving in some hidden cave somewhere. These biscuits last longer than flour as they have a lower moisture content and water activity. One disadvantage is that sea biscuits will absorb moisture if the humidity increases. This was a problem when Royal Navy ships first traveled in the tropics.

When I travel, even on short journeys, I am in the habit of carrying some food and water with me. Travel delays on trains and planes have been part of my travel experience and I prefer to know I have food rather than hope I can buy something if necessary.  Travelers need food that has a long shelf-life, is robust, safe to eat, and calorie/nutrient dense. Many travelers’ food is dried as removing the moisture  extends the shelf life by essentially making the food inedible to bacteria. While removing water has the advantage of stopping bacterial growth, it doesn’t always give us a food that is robust and could stand up to the rigors of travel. There have been a number of times I have reached into my rucksack for a cookie/biscuit and found crumbs. Not the snack I was hoping for!

The sea biscuit has more in common with Terry Pratchett’s Dwarf’s rock cakes than any modern cookie or cracker. So robust that, typically sea biscuits need to soaked overnight or smashed with a hammer or rock to able to eat it. Sea biscuits are the original cracker that was crumbled into New England chowder, probably because that was the only way the biscuits could be eaten. The British navy used to bake/dry their biscuits 4 times. So if you think biscotti are hard to eat without dunking, double the force needed to bite into a sea biscuit and book that trip to a dentist to replace your teeth. They were so hard that apparently an American civil war soldier wrote a letter on the side of a hardtack and mailed it with the address on the other side and it survived in the mail without any protection. No wonder British soldiers were envious of American food rations in World War 2.

In the process of making sea biscuits you knead the flour and water together. This allows for gluten formation and most of the recipes have a 2:1 ratio of flour to water which is perfect for gluten formation. Gluten is the protein that gives bread its springy texture and the network of gluten stays in place once heating is complete which means that bread keeps its structure after baking. While soft bread goes stale very quickly due to the retrogradation of starch, the starch in hardtack is probably all retrograded before leaving the oven. An interesting question would be to find out how much starch granules hydrate and swell in making of sea biscuits. Is enough for the starch molecules to gelatinize? Perhaps the water is removed too quickly for gelation and retrogradation occurs very quickly with little rearrangement of the starch molecules. (Confused – see my post on starch here!)

If you want to make your own sea biscuits there are lots of recipes online due to reenactors and survivalists wanting a food that is traditional and/or last a long time. They are also popular in Hawai’i and Alaska. Personally I would prefer water biscuits or Scottish oatcakes carefully wrapped than a food that is hard to eat. Trail mix would be more desirable still. However, if a zombie apocalypse is ever threatened, I know what I could bake to help my long term survival.


All references visited on 29 January 2018

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Tasty Tuesday: Sugar Chemistry

I really should just sent you to Exploratorium which has an excellent section on sugar chemistry, but sugar chemistry is so cool, that I have share it with you myself.  In fact sugar chemistry is so interesting that it supports a whole sector of the food industry.  I am, of course, talking about candy.  Food Scientists typically divide the candy industry into chocolate and non-chocolate candy and most of the non-chocolate candy is made from different forms of sucrose.

If you remember sugar is the common name for sucrose, which has the very confusing chemical name of β-D-fructofuranosyl-α-D-glucopyranoside which is a fancy way of saying that it is made up of glucose and fructose.  In this post, I will interchange the words sugar and sucrose, but in chemistry sugar refers to saccharides which  are considered to be small carbohydrates.

The most important property of sucrose is its high solubility over a wide temperature range.  The different sugar candies are made by heating a sugar-water solution, as the heating time increases water evaporates.  This increases the sugar concentration and the temperature of the solution increases.  The temperature of the solution is dependent on sugar concentration:

Effect of Sucrose Concentration on Temperature

Effect of Sucrose Concentration on Temperature

Candy technologists not only control the sugar concentration by heating the sugar-water mixture to a predetermined temperature, they also control the final physical arrangement of the sugar molecules by the other ingredients added and by the way they treat the sugar-water mixture while it is cooling. This determines whether the solution sets in a crystalline form or not.  The non-crystalline form is also known as amorphous.  Thus sugar candies are divided into crystalline and amorphous.

Crystalline candies include fudges, fondant and rock candies. Amorphous candies include cotton candy, hard candy and brittles, where the sucrose has been set into a glass, and caramel and taffy, which are chewy rather than hard.


For Figure:

Wikipedia Candy#Sugar Stages

Harold McGee On Food and Cooking 2nd Edition p681

Non-Enzymatic Browning Introduction 2

Food tastes best when browned.

Food tastes best when browned.

Food in always complex unless you are studying something quite simple such as a beverage with few ingredients (vitamin water, anyone?).  Even sucrose has a complex chemistry, more of which I will share in a future post.  So individual NEB reactions cannot be isolated in food.  Quite often intermediates and products from one reaction become intermediates in another reaction, especially in the Maillard reaction. Thus, most food chemistry textbooks use Non-Enzymatic Browning (NEB) as synonymous with the Maillard reaction. However, the other NEB reaction cause browning in food without the use of enzymes.

Both caramelization and lipid oxidation cause browning in certain foods, i.e. sugar-based and fried foods, respectively. Ascorbic acid degradation is significant in food with a low pH (high acidity) especially in citrus juices.  The reaction of flavanoids is important in highly colored foods as the colorful anthocyanins degrade and lose their color.  The reaction of flavanoids may also be important in soy protein, but less because of a color change and more due to a lose of isoflavones.

NEB Intro Part 1

Non Enzymatic Browning

My major interest in food chemistry is how food changes during processing and storage.  I am especially interested in how color changes take place.  The reactions I am interested in are called Non Enzymatic Browning reactions to differentiate them from the browning that occurs when you cut an apple or banana, which involves an enzyme.

Non enzymatic browning (NEB, non enzymic browning) reactions are the most important reactions in food, and, no, I am not biased.   Just image the aroma of melting chocolate, freshly baked bread or  a roasting leg of lamb, the golden color of a croissant, the dark amber color of a well brewed beer; caramels, toast.  These are all caused NEB reactions.

There are five different NEB reactions and I intend over the next few months to write about each of them:

  1. Caramelization – browning of sugar, especially sucrose
  2. Lipid Oxidation – the oxidation of fats and oils; including rancidity
  3. Break down of flavonoids – highly c0lored compounds can also lose their color
  4. Degradation of ascorbic acid (Vitamin C) – AsA is unstable even without oxygen
  5. The Maillard Reaction –  reaction between carbonyl compounds and amino acids

Numbers (3) and (4) are not typically on a list of NEB reactions, but I did my thesis on ascorbic acid browning and it definitely goes brown without oxygen and without enzymes.  The degradation of flavonoids is one I have added and came to me in flash of inspiration when at a conference.  I am sharing it with you now, so this is new even though I had the idea three or four years ago.

More later…

Food Labeling

The March issue of Food Technology arrived and as always I turned to the last page, which is Perspectives*. This month Joe Regenstein has a very good comment about labeling and hiding information from the consumer is hurting the industry.  As he says:

The irony is that the activist community has had much more success in attacking the food industry for not labeling products than it really has had in convincing consumers that the technology is bad for them.

He goes on to protest about the misleading labeling, that really has no meaning:

And finally, what about all those terms we’re sticking on our labels (and in our advertising) that are sometimes justified but just as often plainly misleading?  For example: free range, natural, local. When these words are misused, we  not only cheapen the words,  but we cheapen the entire food industry.

So get with the act, food industry folks and tell what is really in our food.

*It is online too, but as a pdf file

Simple Sugars: Fructose, glucose and sucrose

Glucose, fructose, sucrose

Glucose, fructose, sucrose

Simple sugars are carbohydrates. Glucose and fructose are monosaccharides and sucrose is a disaccharide of the two combined with a bond.  Glucose and fructose have the same molecular formula (C6H12O6) but glucose has a six member ring and fructose has a five member ring structure.

Fructose is known as the fruit sugar as its make source in the diet is fruits and vegetables. Honey is also a good source.

Glucose is known as grape sugar, blood sugar or corn sugar as these are its riches sources. Listed in food ingredients as dextrose.

Sucrose is the sugar we know as sugar or table sugar. Typically extracted as cane or beet sugar. If sucrose is treated with acid or heat, it hydrolyzes to form glucose and fructose.  This mixture of sucrose, glucose and fructose is also called invert sugar.

Nutritionally, these sugars are the same as they all provide 4 Cal/g. This is true for starch and other digestible carbohydrates too. Of the three sugars, fructose is the sweetest and glucose the least sweet, so typically less fructose can be used than table sugar (sucrose) – if sucrose has a sweetness of one, fructose is 1.7 and glucose 0.74

Fructose is more soluble than other sugars and hard to crystallize because it is more hygroscopic and holds onto water stronger than the others. This means that fructose can be used to extend the shelf life of baked products more than other sugars.

Wikipedia has lots information on sugars, including information on the three I am interested in fructose, glucose and sucrose.

Molecular Gastronomy is Part of Food Science

In a recent issue of Food Technology, the magazine for IFT members, Hervé This responds to the suggestion that molecular gastronomy is part culinary art and part science. He gives a very good summary of the differences between cookery/culinary, food science and food technology:

“Cooking is a technique (sometimes an art) and the objective is to make food.”

“On the other hand, molecular gastronomy is a science. It is performed in a laboratory.”

“Furthermore, science is not technology. Thus, applied science cannot exist. Application involves technology (from techne, doing, and logos, study). When examining mechanisms of phenomena, the goal is not to apply knowledge (application), but rather to produce it.”

He admits that he himself had problems during his thesis of separating out science from technology but he states very strongly that molecular gastronomy is science and molecular cooking is using the results from molecular gastronomy to create new food items or improve old ones. This’ Ph.D. thesis, on Physical Chemistry of Materials, was entitled Molecular and Physical Gastronomy or the equivalent in French.

The confusion between the science, art and technology of food is present in food science. That there does not appear to be a final definition of molecular gastronomy adds to this confusion, especially as chefs have taken over this term, rather than using This’ preferred Molecular Cooking. Khymos gives a good summary of the different definitions.

I do have problems with the fact that Molecular Gastronomy is so trendy and considered to be the saving of the world’s food supply.  [So I exaggerate? What’s the problem?] Many articles about Molecular Gastronomy and the restaurants that practice molecular cookery appear to have never heard of food science.  So I appreciated the fact that This states that molecular gastronomy is part of food science but I struggle to place it within the traditional subject areas of food science.  It overlaps mostly with food chemistry.  At least This’ part of Molecular Gastronomy is heavily physical chemistry based.  The research undertaken is more directly relevant to cooking and culinary arts than much of food chemistry.  For example, my research on the Maillard reaction has few direct practical applications, unless you are willing to mix amino acids and sugars together in your kitchen.  I still would not recommend eating the results of my research.

Within the article he gives an excellent summary of what science is – the idea of testing a hypothesis to give new information which increases our knowledge of a system.   I might even use some of these ideas for teaching.


Hervé This Molecular Gastronomy vs. Molecular Cooking Food Technology December 2008 (PDF)