Kitchen Science

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Sarah developed a bunch of food allergies and is using her science skills to find ways to make her favourite foods. Her allergies include dairy, gluten, and eggs – think of how many foods have those ingredients! I had similar allergies as a child and had limited food options because alternatives didn’t yet exist. For example, I ate my corn flakes with water. You get used to it but I’m glad that people like Sarah are experimenting with the options.

 

I’m here today to talk to you about icing.  Yes, that icing, the tasty frosting stuff on top of your cakes and cookies.  Why, you may ask, would I chose to post about icing, rather than the cake or cookies themselves – especially as a guest post?  Valid question – but I maintain that icing is important!

As a child, I actually really didn’t like frosting.  I found it too sweet, but otherwise flavourless, and as a baker it was time-consuming to make.  It wasn’t until I was given the challenge of creating dairy-, egg-, soy-, gluten-, and refined-sugar-free baked goods that I realized how hard some recipes are without icing. Black and White Cookies, for instance, are just plain cookies without icing. Gluten-free cakes can be pretty dry without some kind of topping.  And it’s really hard to make a layer cake look pretty if there’s nothing to cover the final product.

More problematically, icing needs to meet some pretty important specifications: it must be smooth enough to spread, but hard enough to set on the final product.  It needs to be sticky enough to adhere to the cake/cookie, and stick layers together.  It needs to be tasty.  And it’s generally required to look pretty.  The most common traditional icing, Buttercream Frosting, is made by creaming together butter and icing1 sugar.  The fat provides thickness and stability.  When kept at room temperature or warmed up, it thins out and can be mixed and easily spread.  When refrigerated, it thickens and stays in place.  You can make icing with water but it will eventually turn hard and crunchy, and lose its softness.  In buttercream frosting, the icing sugar provides a soft, sweet thickener that helps bulk out the fat into something tasty, fluffy and shiny.

1Icing sugar, powdered sugar, and confectioner’s sugar are all the same product – a very finely ground form of white sugar, often with an anti-caking agent added

Extracts (vanilla, almond, coconut) or citrus juice and zest (lemon, orange) can be added to buttercream frosting for flavour, and chocolate icing can be made by mixing in melted chocolate or cocoa powder.  (Because of my strong aversion to oversweet icings, I often add almost as much cocoa powder as icing sugar to my chocolate icings.)  As a child, we mixed our buttercream with a fork, which left a thicker, shinier icing we spread using a knife. Buttercream can alternatively be whipped to give a fluffier consistency, which can be spread or piped onto a final product.

Several variations of buttercream, including Royal Icing (used for elaborate cake decorations) add egg whites to the usual butter and sugar, for more structural support.  At the furthest extent of this trend, meringue (whipped egg whites, with or without sugar) is commonly used to top pies, as well as the occasional cake or cookie.  Cream Cheese Icing, the classic topping for carrot cakes and spice cakes, adds cream cheese to the traditional butter and sugar, for extra flavour.

[learn_more caption=”Cream Cheese Icing Recipe”]For those of you who can still handle cheese in your diet, I thought I’d pass along my killer cream cheese icing recipe. It’s certainly not doing me any good at the moment, but its deliciousness should be spread and shared. 8oz cream cheese*, softened ¼ cup butter or margarine, softened 1 cup sifted confectioner’s sugar ½ tsp vanilla extract Zest of ½-1 lemon (my secret ingredient – it adds a brightness and surprise flavour that totally wakes up every cake) Cream together cheese and butter. Add vanilla and zest. Gradually add sugar. Refrigerate. *I use ½ regular, ½ low-fat cream cheese, to make a slightly healthier alternative while still preserving the flavour. I wouldn’t recommend using all low-fat cream cheese, though, as the icing gets very thin[/learn_more]

Possibly my favourite pre-allergy cake topping option was Chocolate Ganache.  Ganache is the rich chocolate cream that’s often used as a filling in fancy chocolates, and is made by melting heavy whipping cream and good-quality chocolate in a double boiler2.  Used hot, ganache can be poured straight over a cake, and will harden into a shiny, smooth glaze.  (This technique is quite messy, but delicious).  If allowed to cool, it can then be whipped into a fluffy icing reminiscent of buttercream, but much richer.  It can then be piped or spread over cakes and cupcakes.

2A double boiler is a gentle, indirect way of conducting heat to substances so they won’t burn or overheat (generally used with chocolate or custards). At its simplest, a double boiler is a bowl sitting overtop (but not touching) gently simmering water.  The heat from the steam will provide enough warmth to melt butter or chocolate or to heat milk, but not enough heat to burn.

So let’s review: all the traditional icings I’ve mentioned use some combination of dairy, eggs, and powdered sugar.  Don’t get me wrong, all these frostings are delicious, and totally valid ways to jazz up your baking.  But I can’t use butter, or cheese, or eggs, and half the time I can’t even use sugar.  Vegan margarines can work in place of butter; but honey, maple syrup, or even granulated evaporated cane sugar like Sucanat won’t provide the smooth bulk normally provided by highly-processed icing sugar. So I found myself with an icing quandary.

My first approach to this conundrum, I’m ashamed to admit, was to avoid it.  I concocted delicious fillings for layer cakes, and left them unglazed.  Or I would serve my cakes with a side of apple sauce (delicious on chocolate or spice cakes), or with dairy-free ice cream substitutes.  Then I experimented by thickening coconut milk with xantham gum3 and sweetening with stevia4.  The final product was tasty enough, but unbelievably runny; and even if I kept my iced cakes refrigerated, they still ended up messy and soggy.

3Xanthum gum is a complex sugar derived from the bacterium Xanthomonas campestris, which is used as a thickening and/or stabilization agent.  Check your pantry – Xanthum gum is one of the most common additives I come across when I read food labels.  It’s a pricey powder, but it’s incredibly potent – I typically use between ¼-½  tsp per recipe.  I keep it on hand mostly because it helps replace the binding action of gluten when I use wheat-free flours; but it’s also useful whenever I need a thickener.

4Stevia, specifically Stevia rebaudiana, is an herbal sweetener that’s starting to achieve more popularity in North America.  Stevia is one of the lowest sweeteners on the glycemic index.  It is, however, relatively hard to make use of – whether in powder or liquid form, it’s incredibly powerful, and it quickly goes from “pleasantly sweet” to “overpoweringly saccharine” and then to “painfully bitter”.  And it doesn’t have the bulk to replace sugar in most recipes.  That said, in liquid applications, like puddings, hot chocolate, or icing, it’s an effective way to replace refined sugar.  It can be quite expensive, but as it’s picking up popularity, it’s starting to be easier to buy it in smaller, cheaper packages.   (Even small amounts of stevia last a long time)

So what finally inspired me to make a successful attempt at icing?  A good friend of mine, who has almost no experience with special-needs baking, volunteered to bake for a gluten-free, sugar-free, soy-free and dairy-free group.  Along the way, she developed a remarkably tasty icing based entirely on what she had on hand and thought would work.  Her mixture?  Vegan margarine, honey, and desiccated coconut.  She had had divided up the tricky job usually assigned to icing sugar – honey provided the sweetness and the sticky binding powers of sugar, while the coconut provided the bulk to make a thick, spreadable icing.  And the end product was delicious and flavourful (and not too sweet!)

I was captivated: it was time to start experimenting.  For my first attempt, I straight-up imitated her recipe (although I used sweetened coconut by accident).  The end product was very tasty, but way too sweet because of the coconut mix up.  It was a bit hard to spread, so it went on thick and stayed that way.  But it was also super-delicious, and went brilliantly with chocolate cake.

Now I was starting to get cocky.  I decided it was time to try what up til now had been the forbidden fruit – I was going to make a layer cake!  I turned to my trusty gluten-free vegan chocolate cake recipe as a base.  For my filling, I plotted a variation of my coconut icing.  This time, I decided to up the coconut flavour, and turned to one of my favourite ingredients – coconut milk.  I took an unshaken can of coconut milk5 and skimmed the solids off the top.  This I used in place of butter.  I mixed in honey, a bit of stevia (for extra sweetness), and a bag of unsweetened desiccated coconut.  The coconut I used was longer than usual, which made for a stringier icing; but otherwise, the recipe was delicious.

5Coconut milk is made from the meat of coconuts – usually from draining the meat, or soaking the meat with water to extract flavour.  When canned, coconut milk will separate into a thicker, fattier layer on top, with thinner more watery milk below.  This is normal, and sometimes useful – for icings, I want the fat, while I like mixing the thinner watery milk into coffee and tea.  Coconut milk is not the same as coconut water, the (delicious, and quite sweet) juice found inside a whole coconut.

For the topping, I decided to attempt vegan chocolate ganache.  As I mentioned above, traditional ganache is a mixture of whipping cream and chocolate.  For my vegan version, I used ¾ cup milk-free semi-sweet chocolate chips, and replaced the whipping cream with ½ cup almond milk and ¼ cup vegan margarine.  (This makes a HUGE recipe, by the way, so I recommend halving it). The margarine imitated some of the fat content of the whipping cream, while the almond milk provided the creaminess of the milk.  This ganache will never whip into a tasty, light frosting like a regular version, but can still be used as a thick, shiny glaze.  I spread my ganache over both cake layers, and then poured it over the assembled cake.  It was extremely messy, but ultimately very delicious.  My suggestion is that you add twice as much ganache as you think you need – I found that mine ran off and ended up leaving quite a thin layer.  Incidentally, this recipe would also work equally well backwards – use the coconut icing to top, and fill the layers with ganache.

Now that I know I can make exciting icings, my innovations have continued.  Recently I was craving lemon cupcakes.  I baked up some sorghum-and-rice-flour vanilla-lemon cupcakes, but wanted a really citrus-y icing. I started by mixing some leftover coconut milk with the juice and zest of a lemon and a bit of vanilla extract.  Then I added in some icing sugar (these were some personal-indulgence cupcakes, and weren’t going anywhere near my friend with the sugar allergy).  However, both coconut milk and lemon juice are quite thin, and even after adding most of a bag of powdered sugar, my icing was too runny.  So I grabbed my bag of dried coconut (finely cut, this time), and poured in most of that as well.  My final icing was thick enough to use, and was absolutely incredible coconut-and-lemon heaven.  A five-star recipe I can’t recommend enough!

Whether you chose to use butter or coconut milk, honey or stevia, coconut or sugar, I highly encourage you to experiment with your basic frosting recipes.  Icing is one of the least-modified foods I’ve run across (after scones and soufflés), but with a little creativity, taste-bud magic is more than possible!

Yummy cake!

[learn_more caption=”Are you a kitchen geek?”]Are you like me – the kind of person who loves to experiment in the kitchen, and is really interested in the science behind food?  Then I recommend you check out “Good Eats”, my favourite cooking show. Alton Brown looks into the science behind his ingredients, his methods, and his cookware as he dives into classic dishes and favourite ingredients – and he’s hysterical while doing it.  I’ve also really enjoyed reading Cooking for Geeks: Real Science, Great Hacks, and Good Food, by Jeff Potter.  It’s a nice mix of science, recipes, and encouragement, although a lot of his suggestions do require a higher budget than I have to play around with. And if you’re interested in what I’ve shared about my own food experimentation, you can also check out my blog, Protocol Box for the Lab at Home.[/learn_more]

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