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Take Me to the Pilot

Take Me to the Pilot

By Greig McGill

Pilot brewing is a process that has undergone a bit of change in purpose over the last decade or so. While many breweries will still brew one (or several) pilot batches to really dial in a potential new beer, the rise of rotation nation has led to a lot more of the old “eff it, we’ll do it live” approach to full scale batches.

Far from being dead though, pilot brewing now serves many different purposes, and a pilot plant or three (oh, to have the space!) might be one of the best little tools a brewer can have up their metaphorical sleeve.

What does a pilot brewery look like?

A pilot brewery is simply a small subset of brewing equipment used to produce a batch of beer. For many of us who have come from a home brewing background, a pilot brewery could be as simple as reusing your old home brewing equipment. Of course, if you’re making that beer at your brewery (and you must if you wish to sell it), you’re going to have to pay excise tax on the results. Or you can register to dispose of the beer after sensory analysis, but Customs and Excise can take a fairly dim view of this if it happens regularly. You will have to keep the exact same records for your pilot operation as you do when you brew a full-size batch, as it’s all still taxable and under control of Customs and Excise.Of course, when homebrewing, we often don’t care too much about consistency, or have an eye to scaling a recipe up. For this reason, it’s a good idea to build a pilot system that replicates your full scale system as closely as possible. Some things such as fermenter geometry, and the thermal and osmotic pressure your yeast will be under will always be unavoidably different, but the closer you can get to process duplication, the better your results will be.

So what are the various reasons we might want to utilise a pilot brewery? Why spend the same amount of time to make 50, 100, or 200 litres of beer that we could spend making 24hL? Well, here are a few. Let’s start with the traditional!

Why? Recipe Development!

Even a relatively small 12hL brewery has a fairly high cost associated with making a new beer. Depending on your efficiency, and the beer you’re making, you can easily chomp through 300kg of grist and 5-20kg of hops. Not to mention an expensive pitch of yeast for a beer you may not brew regularly enough to get multiple generations of yeast from. Then there’s the tank time, and opportunity cost of another beer. You’re going to want to nail it. If it’s a style you’re new to, a new-to-you technique you want to use, or just some ingredients you’re unfamiliar with, you might want to minimise your risk by creating a smaller batch first, or multiple smaller batches until you’ve really dialled it in and are ready to scale it up to the production system.

This was historically what a pilot system was for. Of course, the cynical brewer might say “why bother? Customers will drink it just because it’s new, so I can just iterate with a few batches and call it something different each time anyway!” Well, maybe. But there’s a price to pay for that cynicism, and although this article isn’t the place for a soapbox, I’ll just leave this here

Why? Batch Homogenisation!

We’ve all heard those comments from customers at some point. “Oh, the first batch was the best”, “It’s fine but not as good as it used to be”, “I remember the batch that came out last year - it was so good”. Yes, we’re small and artisanal. Many of us don’t mind too much if our beers vary a little in their particular flavour profile from batch to batch, so long as the quality is consistent. Some even tout that variation as a strength. However, if consistency is important to you, a pilot system can be invaluable in maintaining it.Ingredients change. From minor malt spec variations unlikely to have much impact in the final product to drastic shifts in oil composition and alpha acid levels in hops between harvests, geographic regions, farms, and even different rows! A pilot system can allow you to try out hop substitutions or ratio variance to hit a target sensory profile when you need to be consistent.

Why? Small Batch Releases!

Whether it’s just to keep those taps rotating, or you have a hankering to make a particular beer that you love but you know won’t sell as well due to not being one of the three styles popular with consumers these days (OK, it seems that I’m not immune from cynicism either), a pilot system can help. You can make a new beer every couple of weeks - or even more for the cost of a few smaller fermenters and some temperature control. You can also make beers that wouldn’t be cost effective for a large batch.

Why? Yeast Propagation!

Finally, your pilot system can serve as a yeast propagator - perhaps keeping a lesser used strain going without having to order a re-pitch, or growing up a larger pitch for an upcoming standard batch.

Gotchas

So you’ve got your test recipe dialled in, or your small batch has been so successful you’d like to make a big batch now. It would be nice if it was as simple as plugging it into your brewing software and hitting the “scale” button, but unfortunately scaling recipes is not an exact science, and will involve you learning your system well enough to get a feel for what is required.There are some general things to consider though.

  • Hop utilisation will be higher - sometimes up to 30% higher. This will depend on the size of your system, your kettle design, and your whirlpool efficiency.
  • Speaking of whirlpools, your full scale one will be longer and hotter, unless you’re specifically allowing for this by dropping the kettle temp first with a heat exchanger. Allow for more volatilization of hop oils due to this.
  • Knock out time may also be much longer, so allow for increased hop utilisation and volatilization of fragile aroma compounds here also.
  • It’s unlikely you’re going to want to measure malt for brewing at full scale at a much finer granular level than “a sack”, or perhaps “half a sack”. Consider this when designing your small version - try to keep things simple, and use base malt at a higher proportion when scaling up than specialty malts. Most of your fermentable material comes from the base malts, but most of the flavour comes from the specialty malts, and a small percentage change in the latter will have a much higher impact than a larger percentage change in the former. You will be able to dial this in over time, and configure your software’s scaling function to allow for it.

Want One?

If you now find yourself wanting to install a pilot brewery, upgrade your existing one, or even add another (and another, and another…) well, we’ve got you covered! Talk to the Brewshop.co.nz team today to get the advice and toys you need!

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