Go with the flow - choosing a pump.

I can’t believe that I could get so excited about a pump and so obsessively invested in choosing the right one - but I did. Yes - all it does is move wine and must from one place to another, so what is there to get fussed about? It turns out quite a lot. As a small winery I decided to have only one pump for all duties, larger wineries of course have multiple for different tasks - though on reflection an emergency back-up might be a useful addition. I should add I do use an entirely separate garden pump for moving water around while cleaning vessels and powering a spray ball.

The choices of pumping mechanism seem to be: centrifugal, flexible impeller, progressive cavity, lobe or peristaltic. I bought a peristaltic. I’m not going to cover all of these options - plenty of articles do that - I’ll simply reflect on the reasons for my choice, and review whether it lived-up to it. My final analysis was that the peristaltic was the most gentle and probably the most flexible of all the options, but also one of the most expensive. Lobe pumps have a lot to recommend them also, but harder to find in the UK, and seemingly even more expensive. A peristaltic pump is extremely simple in operation, the pump has an integral hose in a C (or U) shape and 2 rollers, set 180 degrees apart, press the contents along and out of the hose, essentially creating a vacuum behind which the next portion of fluid fills, and so on. The 2 rollers mean the hose is never ‘open’ so there is never a let-up in pressure, and no back flow. It’s gentle and the wine is never in contact with moving parts, just one continuous hose.

I was looking for one machine that could move liquid of varying viscosities and must (containing at least some solids) . I needed variable speed as moving 2000l tank to tank is a very different task from racking 100l barrel to barrel, or running through a partially blocked filter (where it is pressure that counts - both that of course is a function of speed). My pump, fitted with an inverter (speed control) can deliver wine between 3000L/H to a speed so slow it is barely measurable, way less than 100L/H. I can run the peristaltic slow enough that I can push wine to within a cm of the end of a hose with no loss of wine, before attaching it to a tank; in some uses - particularly rousing / recirculating tanks- this saves the wine a huge amount of oxygen exposure. Equally when filling barrels I can minimise spillage by running at extremely slow speeds. A peristaltic is also reversible, there are certain tasks where this is of great benefit, meaning that you can change direction without uncoupling hoses - saving time, spillage and oxygen exposure.

Unlike some systems it can genuinely run dry for an indeterminate period as the liquid is not needed for cooling or lubrication. Indeed the liquid does not come in to contact with any moving parts at any point, so there is no danger of contamination, nor damage to the wine from high speed rotating parts - it is extremely gentle. I’m told you can move live fish with it.

As it can run dry it can also lift wine out of a barrel or amphora, in other words you can insert a racking cane into the vessel, fill the cane with inert gas, then run the pump - it will lift the wine out and the ‘head’ of the wine is cloaked in gas, so no air exposure for the wine in the hose.

The one task I was most concerned about with a pump of this nature is filtering, many guides indicate that a peristaltic system is not suitable for pushing wine through cartridge or plate filters. The primary reason is that it will continue to build pressure against a closed system; a partially blocked filter will increase pressure build-up which in turn will further block the filter, and potentially damage the whole system including the possibility of rupturing the filter, necessitating starting from scratch with a new filter. In fact very few pump systems will continue to operate against a closed system without building pressure - centrifugal being the most common that does to an extent. However a centrifugal pump is quite harsh, and also poses a great danger of dissolving oxygen into the wine - not what you want on a bottling line. I haver found that I can happily use the peristaltic while filtering if I use a filter that is a little larger than one might choose for given quantities and flow rates (i.e. reducing the propensity for blocking) and running the pump very slowly: filter sizes have recommended delivery rates, I keep below these. I also keep a constant eye on the filter pressure gauge and adjust the pump accordingly. It is also claimed that the slight surge in pressure created by a peristaltic system contributes to blocking a filter, and can push material through a non-absolute filter - this has not manifested as a particular problem for me yet, and all my bottling to date has had the peristaltic deliver wine to cartridge filters.

I recently had a remote control fitted to the pump - an expensive addition but one that has made some tasks much easier to achieve solo. Where previously we needed somebody stationed at the pump as well as at the business end of a hose, now the one person can mange both. Well worth it.

The alternatives. We occasionally use siphoning to move wine out of barrel - very gentle, easy to set-up but extremely slow and only acceptable for small quantities. I have experimented with a bulldog inert gas (nitrogen) racking device, it was fun to use, gentle and quiet but it is only really useful for emptying barrels, not filling them: it’s too easy to over-filll and spill, and unlike a pump the switch-off is not instantaneous. I’d love to have one, but at £1k its not worth if for the small use it would get, for a task the peristaltic does more or less as effectively.

One thing it does not do as well as hoped is move crushed grapes, either from a lower valve on a vessel, or using a tube / nozzle attachment (like a vacuum cleaner). It picks some up, and moves them well enough, but if there is air rather than liquid around the fruit it won’t pick-up the berries. To do this effectively one really needs a hopper and auger set-up, snd to be honest once we’re shovelling fruit into a hopper, in a winery of our size we might as well shovel it into the destination vessel or press. To her clear it will happily move and pass grapes that are held within a liquid.

I imagine that it would not work well on a gravity feed bottling as a stop cock closes against the pump when the header tank is full, the pressure build-up would be problematic. It would be an effective tool here if the stop-cock was a solenoid that turned the pump off.

I should get a back-up pump, the peristaltic failed on me once (my fault) and I was stuck with wine in the wrong place. I think a small, slow flexible impeller would do for emergencies.

Albin ALP30 purchased from TS Pumps.