Juniper is the heart of gin. The nuanced dance of piny, woody and herbaceous notes that juniper berries infuse into our gin is what gives this spirit its soul.
However, capturing its full potential demands respect, understanding, and more than a little planning to fully master.
For those interested in making a gin, or just refreshing their distilling knowledge – here’s a little more about the berries themselves, how to select them, manage your supply and set objective quality parameters to ensure you maximise the chance of creating the best possible gin.
Understanding juniper
Before we dive into the practicalities, it’s worth taking a moment to understand what juniper actually is. Juniper, a member of the cypress family, is a small shrub that produces berries. These berries (technically pine cones), when mature, have a dark blue colour, and it’s these mature berries that provide the characteristic piney, sweet flavour to our gin.
Not all juniper berries are created equal, and not all are used to make gin. Different juniper species have different flavour profiles. Even within the same species, different regions have different characteristics (with some more citrusy, other’s woody and others more peppery etc.).
In the world of gin unless otherwise stated Juniperus communis is the variety that is being discussed. If you are a maker looking for a local supply, state this. There have been so many producers over the years who say they want to use local juniper, but can’t get the typical resinous pine notes – only to find out the reason is simple. They are not using that kind of juniper!
Beyond the traditional Juniperus communis
Due to their brown and red berries, Juniperus phoenicea, Juniperus turbinata, Juniperus oxycedrus (aka Cade) and juniperus occidentalis (aka western cedar) are obvious to spot as being different.
But the differences in Juniperus procera are a little more subtle, as are many of the Mediterranean varietals like Juniperus thurifer, or the more northerly Juniperus horizontalis (very common in the UK). Some just look like mini versions of communis…
That’s not to say they can’t be used. They can offer an authentic local accent to a gin. For example, Ashe juniper and Alligator juniper give American producers some interesting alternatives, while the door is wide open for a Mexican producer to step into their region’s unique offerings.
In their case, Juniperus blancoi, jaliscana, gamboana and durangensis are four varieties endemic to Mexico and would provide truly distinct and terroir driven gin expressions if used in the right doses.
Legalities and safety
There are legalities to consider. There is no problem using other varieties when using a local juniper in conjunction with Juniperus communis. But EU law does specifically state the varietal communis is what Gin is made from. So replacing it all-together is in direct contradiction to that. It’s worth checking your local legislation to see if it’s specified, or if it’s just termed juniper, which can then be open to interpretation…
With regards to safety – understand that deviating from communis as a variety means stepping away from the known properties and the known distilling science. Do your research and check to see that what you are distilling is not going to cause health issues. For example, it is wise to avoid Juniperus sabina.
The constitution of Juniperus communis
Detour done, let’s get back to the usual star of the show.
The primary aromas are piny, woody and herbal, largely due to a high terpene content. Terpenes are a set of aromatic hydrocarbons found in numerous plants and botanicals.
When it comes to juniper, α-pinene is the most abundant terpene (making up to 50% of the total aroma molecules). It gives gin a woody, pine-forward scent. Other important terpenes found in significant amounts within juniper include sabinene (which also gives a woody sappy pine note), myrcene (which tends to be herbaceous and hoppy), and limonene (citrusy) and β-pinene (which has a lighter grassy pine aroma).
By thinking of juniper as a combination of compounds, not a singular ingredient, you can start to hone in on the specific requirements you are looking for.
For example, those who want a sappy resinous classic gin profile might gravitate to juniper sources with particularly high α-pinene content. Say, Macedonia or Tuscany. Others seeking a woodier profile might favour somewhere else, say from the Himalayas or Lebanon.
It’s both the beauty and the endless quest for gin makers. Each botanical is a moving part, let alone how you then combine them in a recipe, or the method of extraction or distillation.
While you can go around in circles and never come to a conclusion with the minutiae of detail involved in the botanical chemistry – the contents of your juniper is an area where it pays to get a handle on the details. It’s a must for any distiller looking to make world class gin.
Selecting quality juniper berries
When sourcing juniper start with the origin. As we stated above, juniper berries from different regions can have subtle variations in flavour due to differences in soil, climate, and growing conditions.
Experiment with berries from various regions to find the ones that align best with your desired flavour profile. You’ll likely be looking for the same region year after year, so have a think about that part. Ask ahead to find out about the politics, supply structures and challenges growers may face.
The next is building a good relationship with your supplier. Discuss harvest schedules, expected yields, and any potential issues that could affect supply. This proactive approach will help you adjust your order quantities in time and prevent unpleasant surprises. Tell them what you are looking for. What matters to you. What your parameters are. All the top tier botanical suppliers like to know their customers inside and out. They want to work with you and service your needs.
Here’s how you can go about setting some objective parameters.
Setting criteria for your juniper supply – sensory and scientific measures
A combination of sensory and scientific methods will enable you to assess your juniper in a thorough, holistic manner, helping you secure the very best for your gin production.
Sensory criteria
Our senses, particularly smell and taste, are fundamental tools when dealing with juniper berries.
Aroma: Fresh juniper berries should have a robust piney scent, which is a good indicator of their potency. If the berries smell weak or stale, it’s likely they’re past their prime and should be avoided.
Resinous quality: High-quality juniper berries often have a resinous quality and a stickiness which comes from the essential oils. When crushed between the fingers, the berries should release an oily film, a sign of healthy essential oil content.
Size: While size does not necessarily correlate with flavour, consistently sized berries can indicate a well-managed harvest, as a wide difference in sizes can signify varying stages of maturity.
Flavour: Taste what they are like by doing trial benchtop distillations of yearly crops. Is it the same as previous harvests, is it what you are looking for?
Scientific criteria
Sensory evaluations, while essential, are subjective by nature. Therefore, incorporating scientific methods can provide a more objective perspective.
Gas chromatography: This method helps you identify and measure the abundance of various compounds in the berries, including essential oils. Using a mass spectrometer, you can analyse the chemical fingerprint of your juniper berries, ensuring they have the right balance of compounds for you.
Moisture content: Using a moisture analyser, you can measure the water content. This is helpful to see how your storage conditions are impacting the botanical and will help you gauge if you need to improve.
Pick and chose whichever you feel you can consistently implement. Combining sensory and scientific criteria creates a robust framework for assessing your juniper berries, enabling you to maintain a consistently high-quality gin output.
Managing your supply
Managing your juniper supply is a delicate dance. On the one hand, you want to ensure you have enough stock to maintain production, but on the other, you don’t want to overstock and risk your juniper berries losing their freshness.
Start with the obvious – monitor your usage trends and maintain a regular communication line with your suppliers.
The next important aspect of managing your supply is proper storage. Juniper berries, like many other botanicals, can lose their punch and aromatic quality when improperly stored, negatively impacting the quality of your gin. Maintaining “freshness” is key.
Temperature, humidity, and air contact will affect the quality and rate of degradation.
Botanicals should be placed in a cool (between 4-10°C) environment. Humidity levels should be low as excessive air moisture can reduce aromas and even aid fungal growth.
A note on dry:
A dry environment is vital for preventing the growth of mold and other harmful fungi. Juniper berries, like most organic matter, are susceptible to fungal infections when stored in damp conditions. This not only spoils the berries and those unwanted flavours will carry over into the gin.
It’s not as evident to see as you might think either, with spores so small that to the eye it’s hard to discern. Often, the mold spores are inside the berries and not on the outside and the first time you realise it is when the maceration smells off.
To keep your juniper supply as dry as possible, keep the bags off the floor and ensure they’re kept in a place with low humidity.
Practical storage tips
- Use the right containers. If working on a small scale, choose containers that provide an airtight seal to keep moisture out and the flavourful aroma in. Glass or food-grade stainless steel containers are good options.
- Location, Location, Location. The storage location should be away from direct sunlight, heat sources, and areas prone to dampness or high humidity.
- Keep it consistent. Frequent temperature and humidity fluctuations can damage the berries. Aim for a consistent storage environment, ideally cold, and avoid moving your stock around unnecessarily.
- First in, first out. To ensure that you’re always using the freshest berries, practice the First In, First Out (FIFO) method. This means using the oldest stock first and ensuring your supply doesn’t sit for too long.
Procurement strategy and batch transitioning
To ensure a consistent supply of high-quality berries and smooth production flow, it’s wise to plan your procurement with a six-month lead time.
Six-months ahead purchasing
You need to strike a balance between ensuring supply continuity and maintaining the freshness of your juniper berries. Knowing your run rate is key to doing this effectively.
With a six-month lead time, you allow for potential disruptions in the supply chain due to unforeseen circumstances such as adverse weather, crop failures, or logistical hiccups. The reality is that many suppliers will not have any in stock for a few months of the year, as they are waiting on supplies. If this is the case, by giving them excessive lead times they can forecast demand and ensure that you order will be met when the harvest comes.
Gradual batch transitioning
Phase it in, don’t switch overnight. Even if the new batch meets all your quality criteria and you’re happy with it, remember that each batch of juniper berries is slightly different.
By gradually introducing the new batch into your production, you allow yourself time to make any necessary adjustments to the distillation process to accommodate the new berries’ subtle flavour differences. This way, you can ensure a consistent flavour profile for your gin, even as you transition to a slightly different juniper profile.
It might seem like a small detail, but batch transitioning is one of those finer points that can make a world of difference to your gin’s year round consistency and quality.
This distiller’s guide is intended as an insight piece into the selection, evaluation, and management of juniper berries.
We’ve emphasised the importance of understanding juniper’s diverse characteristics, the nuances of sourcing, and the critical aspects of storage and batch transitioning. We’ve shown why and how to combine both sensory and scientific methods for quality assessment, as well as factors to consider when managing your supply.
Now that you’ve got the low down – use it to strike the right relationship between botanical quality, consistent operations and finding the right flavour profile for your gin!
