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The bottling department of your distillery is a paradox: your biggest value-add is putting corks in glass, but bottling carries a lot of technical and regulatory challenges. Let’s go through these challenges and examine some solutions. When I refer to a bottle, I’m speaking of a standard 750mL filled with 80 proof spirit.
Technical
Bottling sounds simple: you just put liquid into glass and cork it. As with most things at a distillery, the devil is in the details. We’ll examine typical craft distillery bottling options, from manual to semi-automatic. (Full-auto bottling lines are out of the scope of this article).
The simplest way to bottle spirits is to use a pitcher or other hand-held vessel and manually pour spirits into bottles, perhaps with a funnel. This method does not scale particularly well but is suitable for short bottling runs and startup producers. Achieving consistent accurate fills is likely to be challenging, and the only way to increase throughput is to throw more labor at the problem. With these drawbacks in mind, there is still a place for manual filling at some craft producers. You can expect 50-150 bottles filled per hour with this method, assuming a single skilled operator.
Moving upwards on the ladder of automation, the next bottling machine to consider is a “semi automatic” standalone or benchtop filler. A popular option in this category is offered by Xpressfill out of California; you can buy their 4-head timer-based filler for about $3,000 and this machine claims it can fill 400 bottles per hour. (Note that this is roughly the same individual bottle filling speed as the manual option, but you can fill four at a time to increase throughput). This filler includes a “dip stick” you can drop into your source vessel; it uses pumps to pull liquid and a manifold to “split” it into four equal streams. Setup and maintenance on this filler can be tiresome, since you must adjust fill times (down to the hundredth of a second) to achieve accurate fills. As your source vessel liquid level drops, so does the head pressure on the bottling machine, requiring periodic timing adjustment to keep the same fill heights. Finally, this style of filler will typically leave you with visually mismatched fill heights. Such mismatches are not necessarily an issue from a regulatory perspective, but some proprietors prefer visually matching fill heights.
Another benchtop filler to consider is the Enolmaster vacuum pump-based filler. This filler can move a bit faster (600 bottles per hour claimed) thanks to a clever vacuum pump and overflow reservoir design. The Enolmaster delivers visually consistent fill heights. Downsides include the need to handle excess liquid in the reservoir, as well as generally fiddly operation – flipping valves in the wrong sequence can easily cause spirit to enter (and destroy) your vacuum pump. This filler is gentle on your end product, but care should be taken to prevent the loss of proof from spirit under vacuum.
The next-fastest option is a volumetric gravity filler. These fillers are common in wine and can operate with no electricity or compressed air requirements. A holding tank is mounted above 2, 4 or 6 filler heads. Clever hardware in the filler head stops the liquid flow at a particular liquid height. These fillers claim up to 850 bottles per hour (4 head). Manually topping up the reservoir is tiresome, so these fillers are often sold with a mechanical float switch and a transfer pump to maintain a suitable liquid level in the tank. Naturally, these pump options do require electricity or compressed air to function. Gravity fillers achieve visually consistent fill heights and are your fastest “semi automatic” option for filling bottles.
In terms of workflow, the Enolmaster and Gravity fillers have an advantage over Xpressfill: Xpressfill requires you to place four empty bottles on the shelf and then wait for all four to fill, simultaneously. In contrast, the Enolmaster and Gravity options allow you to add and remove bottles arbitrarily during fill operations, which can increase throughput and efficiency (replacing bottles two at a time instead of four at a time makes better use of your labor).
Regulatory
Bottling is when tax determination takes place, so TTB and its regulations are some of the strictest in all of 27 CFR 19.
You are allowed a tolerance on your fill heights, ranging from 1.5% +/- to 4.5% +/-, depending on the size of your bottle. This tolerance seems generous – a 750mL bottle enjoys a 2% fill tolerance, meaning you can put as little as 735mL or as much as 765mL in that bottle while remaining compliant.
If you stop here, you might think bottling is easy. But there’s more to the fill height regulations. DSPs must hit the labelled fill height on average. That is, if you have 735mL fills, you need just as many 765mL fills so that you achieve a 750mL fill on average. It is not optimal to have such wildly varying fill heights, so in practice, you want to stay as close to standard fills as the equipment will permit.
You might be wondering how you can have compliant filling operations when using both visually inconsistent (as with the Xpressfill) as well as visually consistent (e.g. gravity filler) fill heights. The regulation addressing average fill heights is the key: regardless of the appearance of your bottles, you can achieve accurate fills on average.
Additional bottling compliance requirements include Fill Test QC and Bottling Tank Gauge, but those are beyond the scope of this article. DISTILL x 5 includes tools to aid you in meeting these requirements. Achieving success is a matter of consistent internal controls and quality recordkeeping.
Final note on glass bottles
The internal volume of glass bottles always varies. This means that bottles that appear to be filled consistently are guaranteed to be inconsistent in terms of actual liquid fill. Conversely, bottles that are filled with a consistent quantity of liquid will appear, visually, to be inconsistent. A wise proprietor balances compliance concerns with shelf presentation and bottling machine cost/benefit analysis.
There is no single “right answer”. A free 20-minute consultation with the author can help you make sense of the options and find the right path forward for your company. Book today and achieve enlightenment! Book your consultation now.
