accidental discovery: walnuts can make things purple?

So I’ve made this recipe belonging to a buddy of mine about five times without any anomalies and consistent flavour. It’s a simple method using an immersion blender, comes up a creamy golden brown, with a little separation continuing after a cloth-straining (no big deal as it’s blitzed into a creamy drink). It’s walnuts, honey, vanilla, water.

Out of nowhere this week, and originally to my absolute horror, as I began blending the walnuts into the honey it began to turn purple… and then black. What the hell had I done? What new element had I introduced? It was practically inky and the foam on top was cement grey-purple.

Turns out this is one the coolest accidents to come my way. It was an acid that is commonly found in the skins of walnuts, called gallic acid. After a bit of google searching I ended up on baking and beekeeping forums, and the wikipedia page of an ink used between the 15th-19th centuries, and this is what I’ve got:

  • A problem for bakers is having their walnut breads turn purple because of gallic acids found in the skin.
  • A highly sought after and quite rare type of honey that occurs naturally is dark purple. Many apiarists believe this is because of high acidity in the soil in the vicinity of hives.
  • Iron gall ink was prepared using iron salts and tannic acids from oak gall nuts (where the name for gallic acid is derived.) A well prepared iron gall ink would gradually darken on the paper to a dark purple colour.

I totally triggered a chemical reaction accidentally. Perhaps the honey contained something that interacted with the walnuts? Maybe I didn’t bring the water entirely to the boil?

Now where do I find this actually purple honey, though?

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using acid to clarify homemade orgeats

For a while I was looking for a method to get my pistachio syrup stable, be it cloudy or clear, without using metres of muslin cloth. (pistachio syrup with xanthan). I actually solved this a little while back and after making it a few times have pretty much nailed down an easy method.

The recipe I was using had a splash of unexplained vinegar in it. For most of the time I have been making it I assumed it must have been included as a preservative measure, as with shrubs, as there was no mention of it in the recipes method. One day however, as I was melting sugar into my pistachio milk on the stove, I noticed a thick skin forming on the top of the liquid, and I began to skim it off, as you might while clarifying butter. So many things clicked in my brain at the same time (citric acid in cheesemaking, alternative milks like soy and almond curdling in hot coffee) and that unexplained splash of vinegar suddenly made sense.

Now I bring that stuff to the boil, stand over it at a simmer with a large flat spoon, and skim as much of that gunk from the surface as I can, and then it’s just one pass through few layers of muslin for a perfectly clear syrup. I wouldn’t necessarily use vinegar in every orgeat recipe I made. In this recipe it works because the pistachio syrup is used in combination with a shrub that also contains the same type of vinegar, so the distinctive flavour is balanced in the final drink. It’s definitely worth looking into how small an amount of acid you can add to encourage it to curdle, to reduce the chances of altering the flavour.

the origins of fat-washing

Read this excellent run down of fat-washing on Serious Eats. I refer to it often, as my knowledge develops, and the more scientific elements the author discusses make more sense to me each time. The best thing to me though, is the discovery that the origins of fat-washing lie in an antiquated perfume extracting technique called enfleurage. There are two types of enfleurage: cold and hot. They’re used to infuse odourless and flavourless animal or vegetable fats with the scents of flowers like jasmine or tuberose that are too delicate for other infusions. In cold enfleurage that fat is spread out in a flat tray and the fresh petals are pressed into the fat. They are left to infuse, and once spent, are replaced with a fresh batch a few times. Once the fat is saturated with the scent, it is washed with neutral alcohol to extract those essential oils. This article on Punch  mentions a peanut butter infused spirit where the creator used this second step of the cold enfleurage method to extract the flavour. Hot enfleurage is faster and good for scents like lavender and rose. The flowers are submerged in hot oil and like with cold, they are spent and replaced a few times, and then the oil is washed with alcohol. I asked a perfumer what kind of oil she used for infusion and she recommended safflower.

I’m hoping that I can use this technique to make my own perfumed fat-washed alcohol. So it might carry some of the silky texture, but mostly it will be far more to create a more aromatic spirit. Like maybe cognac pumped up with rose.

tactile experience: szechuan pepper

I’ve been thinking more and more about how important the feel of a drink is. I’m talking literally texturally. I’ve been coming at the idea from a few different directions for a while now, and have just realised that in all cases I’ve been playing with the same concept of messing with the sense of touch.

Most recently I started thinking about if there was a way to make something tickle a little, or give the impression of actual movement beyond carbonation bubbles, and I stumbled across an article about an experiment with Szechuan pepper. Szechuan pepper has a little guy in it called (hydroxyl alpha) sanshool which actually produces a tingling sensation akin to vibration. Apparently this vibration (measured in studies at a frequency of 50.0 Hz: Science20) can give your tongue and lips the impression that a drink of still water is actually fizzy.
This suggestion got me pretty excited, because I have been mulling over some ideas for a drink or drink/food pairing for a while, that might trick you into thinking a still drink was carbonated. Perhaps there is a sound track of the very light, tickling crackling sound of teeny bubbles, or the food, a dust on the rim of the glass or a mousse (emulating carbonation foam) on the top has something like pop rocks in it. Sanshool might solve this! So how to infuse/extract it? Can I find it in foods other than Szechuan pepper?

foams, airs, mousses

When you consider texture in drinks that often only extends to the viscosity of the drink as a whole, often in relation to dilution or the desired impact of the flavours. The light astringency of citrus or other acids is great for palate cleansing aperitif style drinks, and the rich tongue-coating effect of chilled gin or vodka is somehow syrup-like and refreshing at the same time. We use foams all the time in sours and fizzes with egg white, but I want to go a step further, and make that layer of foam a separate flavour. I’d seen chefs using coarse foams on dishes, and the last few iterations of the menu at work have included a drink or two topped with a dense, egg white based, flavoured mousse.

Recently, talking with my workmate, Jimmy, we were pondering how to incorporate the sweet distinctive flavour of cola into a cocktail without it immediately dominating the drink. He suggested a flavoured foam, of the style we already used (the dense, egg white based mousse), and it got me thinking about the huge volumes of effervescent fluff you create when you first open and pour a room temperature bottle of carbonated soft drink. It’s even better if you’re pouring the room temperature drink over ice. The fast temperature change must shock it into foaming up even more. In my experience Diet Coke is best/worst for it. (Waiting for your mixer to settle when it’s busy is the worst.) So. what if the foam was actually that light, aerated froth rather than something dense and almost creamy, and how was I going to get it to keep its form for longer than a few minutes?

Peering over shoulders in kitchens had informed me that the creation of a flavoured, beer-head style froth was a pretty common technique, so I turned my research to culinary foams, which has been enlightening. There are wet foams and dry foams, coarse foams and airs with large bubbles, and dense mousses with tightly beaded and bonded bubbles. I even learnt that bread is a “set foam”, which actually makes a lot of sense coz when you look at slice of bread its whole structure is a network of bubbles. I’ve seen Lecithin powder amongst the modern ingredients of the top shelf in the kitchen, so tomorrow, armed with the very handy digital scales, I’m going to attempt a flavoured, (and coloured), coarse foam/air.

So far I know:

-Soy Lecithin is a commonly used stabiliser and emulsifier, which can be used to replace the lecithin that naturally occurs in things like egg yolk.
-The liquid I’m trying to foam will need to be very strong, because I’m going to be diluting it so much with air.
-I should be trying to add by weight at a volume of 0.3%-1% of the total liquid, depending on what I’m trying to foam. A recipe for a citrus foam that I’ve found uses something close to 0.6% of total volume, but I was planning on my foam being made from a starting liquid that was a little denser, so I’m not sure how that will impact it yet.
-I need to mix the foam in a low flat container with something like a stick blender, to allow as much air interaction and incorporation as possible.

More on this later.

sound is important to your perception of flavour

Things taste different in planes to on the ground so when a chef curates an inflight menu, or a sommelier writes a wine list for an airline, they have to consider this as they select ingredients and flavour profiles. The altitude, background noise and dried nasal passages alters the way you interact with flavours. Salt perception is reduced, for example, but umami is enhanced. Apparently tomatoes taste amazing because of this, and in hindsight I think of all the very sad looking slices of “fresh” tomato that I have pushed aside on inflight meals. What if I was missing out on something amazing.

Studies have found that sound contributes immensely to our perception of flavour, with my favourite being the 2007 University of Leeds study (called “Bacon: the slice of life” omg) which was conducted to quantify just how important the crispiness of bacon is to the perfect BLT. This kinda thing is pretty common in commercial food science which I imagine often results in “new & improved” products on the regular. This Flavour Journal article references a Magnum icecream improvement that went wrong when they accidentally altered the way the chocolate coating cracks as you bite into it.

And then there’s ambient noise, like music. Studies have proven that music played at higher decibels influences people to perform activities faster, drinking in particular (ScienceDaily), which is a pretty neat trick that a lot of fast moving venues employ, but something that potentially inhibits your perception of the food and drink you’re consuming there. (Maybe that’s why some restaurants choose not to play any music at all?) There’s also evidence that that background music could be altering your palate too. Low pitched tones focus our palate on bitter flavours and high tones bring out sweeter flavours. You can test it out on yourself here: high pitch, low pitch. Apparently something like coffee or dark chocolate is a great thing to try it out with as it has distinctive sweet and bitter notes.

absence of flavour

I like to write ideas down to research later, so I often find snippets written down on the backs of receipts used as bookmarks or stuffed at the bottom of a bag I last used a few weeks ago. Then I get to decode my scrawl and try and figure out where the curiosity was focused.

This one was pretty interesting,
if you ate something that tastes like absolutely nothing would it enhance or dull an accompanying drink?

Turns out, there’s not much that tastes like nothing. Maybe just water that’s free from the chemicals our nose or tongue can detect, straight from a pure source. There is a neutral baseline, but it’s kinda gross so it killed this idea pretty fast. It’s our saliva. That’s why pure water tastes neutral. Our saliva is 98% water. The other 2% is made up of substances such as electrolytes, minerals like sodium and potassium, mucus, antibacterial compounds, and enzymes.

On a side note, a pretty neat trick for nosing spirits and wine is to smell your own skin to set a neutral baseline, (obviously this wouldn’t work if you use very fragrant soaps or perfumes.) This is helpful when you get overwhelmed with trying to pin down that one elusive note as well.

I think that potentially you could make a food very neutral flavoured, perhaps with gelatin, but if it were to enhance the drink then it would need to have some interesting textures going on, and that would be pretty hard to achieve while still retaining as little flavour as possible. Also, you’re trying to replicate the flavour of saliva, and I just don’t think you can sell that.