The Basics

Sour ingredients such as lemon juice can change a cocktail in several ways, it is also probably the most popular and essential ingredient used in mixology. But what is the ideal amount to use for a cocktail or is there any at all? There are three angles we have to look at, so at the end we can get a much clearer picture.

First, lemon juice obviously provides the sour side to a drink, second, it reduces the very intensive and characteristic aromas of the base spirit helping to blend the different ingredients together. And third, coming from the first point, lemon juice gives a fresh and clean feeling to the cocktail by bringing flavours more forward, but only if the whole drink is well-balanced.

However in terms of aroma contribution, two parts of the fruit is used in making cocktails, the juice as an ingredient during the mixing, where lemon peel primarily has a role in the final touch by expressing its essential oils or garnish a drink. We have to differentiate between juice and oil and look at their aroma compounds separately. I am also quite sure that people tend to underestimate the use and effect of the oil in the peel in cocktails, although it gives much more flavour and character than the juice.

Lemon juice

Coming to the lemon juice we have to look at its character, the sourness, where it is coming from. There are mainly three acids that are responsible for this taste, namely citric acid, ascorbic acid and malic acid. Let’s look at each of them separately:

  • Citric acid: It is present in greater amounts in a variety of fruits and vegetables, most notably in citrus fruits. Lemons and limes have particularly high concentration of this acid, it can constitute as much as 8% of the dry weight of these fruits. Citric acid is a colourless, translucent crystal or powder, odourless, but it has a strongly acidic taste, a tart and sour flavour.
  • Malic acid: It has a clean, mellow, smooth, persistent sourness and a smoothly tart taste. Malic acid contributes to the sourness of green apples for instance, it is present also in grapes and gives a tart aroma to the wine.
  • Ascorbic acid (Vitamin-C): It is odourless and has a pleasant but bitter, sharp acidic taste.

Lemon oil

Lemon oil expressed on the finished drink is normally the conventional way of using this part of the fruit, however I believe that we should play with it and use it also inside our drink as it contains much more aromas than the juice. The oil contains relatively low level of limonene (more than 70%) but quite high level of α-pinene (1–2%), β-pinene (6–13%), sabinene (1–2%) and γ-terpinene (8–10%), this last component is the one responsible for the greeny peely odour. Lemon oil is fairly unstable, quality can change with careless storage, resulting in a bad or damaged taste.

Let’s have a look at the different constituents how they contribute to the overall aroma profile of the lemon oil:

  • Limonene is the main component of citrus oil (more than 70%), responsible for the unique citrusy aroma. Limonene is a colourless liquid with a pleasant lemon-like odour and a fresh citrus taste.
  • Alpha-pinene (1-2%): It is found in the oil of many coniferous tree species, most notably in pine tree, but it is also present in the essential oil of rosemary. The odour is quite characteristic piney and turpentine.
  • Beta-pinene (6-13%): Among various plants and herbs, this chemical compound can be found in allspice, ginger, nutmeg, bitter fennel, rosemary and sage. It has a characteristic turpentine odour and dry, woody and resinous aroma.
  • Sabinene (1-2%): This woody, spicy, citrusy and terpy with green, oily and camphoreous compound is usually present in essential oils of plants such as black pepper, holm oak, Norway spruce or nutmeg. Sabinene is the reason behind the spicy element of black pepper.
  • Gamma-terpinene (8-10%): It is a major component of essential oils found in citrus fruits and has strong antioxidant activity. The oil of savin, american wormseed, coriander, ocimun viride and ceylon cardamom also contains this terpene. It has a, citrus, lime-Iike, oily, green odour with a tropical fruity nuance.

Let’s mix

To try everything in practice I have chosen to look at 4 different combinations to see how the lemon juice changes on the taste of the spirit. The best way is to try it on very floral fruity palinka such as grape or apricot as it is easier to see how the more volatile aromas are changing by adding the sour ingredient. For the experiment I use 25ml of the Irsai Oliver Grape spirit by BARKA and adding 6.5ml, then 12.5ml and finally, 25ml of lemon juice.

Test #01 – 6.5ml lemon juice
  • Nose: It is very close to the neat spirit, fresh without noticing the citrusy aroma too much, however the lemon juice is definitely there without losing the fresh aromas of the spirit and also significantly decreasing the pungent alcohol smell.
  • Taste: We can see a pleasant bitterness and sourness appearing without overbalancing the spirit, most of the floral fruity aromas are still present. This amount of juice is sufficient to decrease the strong alcohol taste, but it is still noticeable.
Test #02 – 12.5ml lemon juice
  • Nose: Lemon is very obvious here, the fresh fruity and floral aromas are in the background however with much less intensity. The strong, pungent alcohol odour completely disappeared, it can only be noticed after a very deep sniff.
  • Taste: At the beginning we can experience the same fruity aroma but it changes quickly to the sour lemon, which is completely overtaking the whole flavour profile by the end of the sip.
Test #03 – 25ml lemon juice
  • Nose: In this The presence of the fresh lemon juice is very obvious, the pungent alcohol smell completely disappeared, less fruity aroma is noticeable but still plenty in the background
  • Taste: Floral and fruity aromas at the beginning for a very quick second but as in the second case the sourness is overtaking even more, it is quite overbalanced to the sour side.

The Verdict

After trying a few different variations, by now we have a much better understanding, however it really depends what we would like to achieve with our drink. Ideally the main aim is to get rid of the pungent alcohol taste if there is any, but keep as much aromas as possible not overbalancing the spirit by too much sourness.

In terms of smell, I would say a good compromise is somewhere between the #01 and #02 variations. As a matter of taste, the ideal combination in order to keep all fresh aromas but smooth the strong alcohol taste out is also between #01 and #02 as in the latter case the pungent taste quite nicely disappeared but we still have plenty of fresh aromas in the mixture to build on.