Winery Pumps: Mobile Hygienic Pumps for Wine Production

Millions of people around the world enjoy a glass of lovely red, white or rose wine. Indeed, some of our team here at North Ridge Pumps have been known to enjoy a tipple or two.

So it was a very welcome commission when we were asked to supply 3 mobile winery pump units to a UK-based winemaker. But before we talk about the winery's pump requirements and the solution we specified, let’s take a closer look at how wine is made. 

The winemaking process

We all know that wine comes from grapes, there’s some squashing involved and then storage often for years in casks or bottles. But what’s the actual process?

Humans have been making wine for thousands of years and it’s a fairly simple method which doesn’t need much supervision. According to National Geographic, evidence suggests that Stone Age people were making and enjoying wine in Tbilisi in Georgia as far back as 6000 BC. 

Although there are quite a few variations in winemaking, there are essentially 6 steps to follow:

1.       Harvesting

The grapes must be picked at just the right time which is usually determined by a mixture of science, tasting and ancient wisdom passed on from generation to generation.

These days, harvesting can be carried out very effectively by machines, or by the old-fashioned method of picking the grapes. Many winemakers still prefer to do it by hand, as mechanical harvesters can be harsh and damage the grapes, vines and soil. 

2.       De-stemming

Next, the grapes are separated from the branches and leaves. This is because these can add flavours and aromas that are bitter for the wine during the maceration stage.

However, for white varieties this isn’t always done because the stalks help remove the must at the pressing stage. With red wines, de-stemming is usually done at the press to remove the stalks and any astringent substances and herbaceous flavours that might be added to the fermenting must.

3.       Crushing

For thousands of years, this was done by men, women and children who trod the grapes in massive barrels or vats and turned them into must. Nowadays, mechanical grinding can improve the quality and longevity of the wine, while reducing the need for added preservatives.

Once the grapes have been crushed and pressed, the must is allowed to rest. It will then start to ferment in 6 to 12 hours by interacting with wild yeasts in the air. Some winemakers use natural fermentation like this, while others take away the wild yeasts and add a different yeast that produces more controllable results.

4.       Fermenting

Fermentation will carry on until all the sugar is turned into to alcohol leaving a dry wine. This can take anything from 10 days to a month. Alcohol levels vary from wine to wine, depending on the amount of sugar that the initial must has.

What’s more, wines produced in colder climates usually have an alcohol level of 10%, while wines made in warmer conditions can have up to 15% alcohol.

5.       Clarifying

Clarification takes place when substances like clay, egg whites and special compounds are added to the wine. These stick to the solids and push them down to the bottom of the tank. The stripped wine can then be pumped to a different container for ageing and bottling.

6.       Ageing and bottling

Ageing is one of the most important steps in the whole process. The wine is pumped into bottles, stainless steel or ceramic tanks or big wooden barrels. Here, it evolves and develops different characteristics and aromatic notes that will be picked up during tasting.

So which wine pump to choose?

Wine is an incredibly delicate and valuable product. This means that a great deal of care needs to be taken when moving it – so selecting the correct pump for your winery configuration is crucial to ensure the quality of the end product is not compromised.

Pumps are used throughout the winemaking and transportation process, including pumping grape must where partial solids might be in the fluid. Pumps are typically needed for wine transfer, filtration, bottling and unloading of trucks, or tanks.

Choosing the right pump for each stage is imperative. Why? It’s because even the smallest temperature change, a little additional force or agitation can affect the final product, such as altering the consistency or flavour of the wine.

In fact, the requirements of the whole winemaking process means that two totally different types of pump are needed: a must pump and a wine pump.

What is grape must and why does it need a different pump?

Must is the residue of crushed grapes produced during winemaking. It’s a fairly thick fluid which is a blend of fresh grape juice and pomace, the solid mixture of grape skins, seeds and stems left after they have been crushed whole.

Must pumps transfer this residue juice and pomace from the crusher to the fermenter, passing the thick must through the pump head. Wine Lees can also be present which originates from used yeast or diatomaceous earth used to filter wine and improve wine extraction.

Later they pump the fermenting wine over itself to break up the cap of grape solids which have risen to the surface in the fermenter. This technique is called pumping over and involves pumping juice up from the bottom of the tank and spraying it over the cap of grape solids on the top.

This means that most pumps require larger pipework and slower pump speeds to minimise wear. Additionally, considerations must be made for technology that prevents the pumped liquid from slipping back to the inlet

Why is a wine pump different?

In short, it’s all about viscosity. Crushed grapes or grape must are around 2000 CPS on the viscosity scale, whereas wine has a very low viscosity of just 1 CPS. 

In short, wine pumps aren’t designed to move thick solids like must. They’re mainly used for moving wine between fermentation tanks, to pump wine after pressing for filtration, bottling and racking, and for filling and emptying tanker trucks.

Whatever the pump type though, all pumps used for winemaking have to: 

• Be fully hygienic and suitable for food grade applications, easy to clean and sanitise

• Be pulsation free and cause minimum shearing or agitation so the wine isn’t damaged

• Minimise the wine’s exposure to oxygen

• Transfer solids and sediment with strong suction lift vital for transferring must

• Be self-priming and easy to switch between low and high transfer rates

• Be portable to move freely around the winery, and easy to operate by all personnel

Choosing the right winery pump

There are a variety of wine and must pumps available, and it can be hard to work out which type of pump is best for which part of the process.

When it comes to moving liquids and solids, different pumps have different qualities and performance capabilities. Certainly, there’s not one pump design that’s suitable for the whole winemaking process. That’s because of the wildly varying nature of the liquids and solids and their different viscosities.

• Progressive cavity pumps

 These are ideal for many of the winemaking stages as they transfer the fluid throughout the process in a very delicate way, from transferring whole or destemmed grapes, to the berry-crushing stage and on to wine bottling.

They have a gentle pumping action which won’t damage or impair the grapes and are available in trolley, hopper and controller options as well as being able to be ran at slow speeds to reduce wear.

•  Stainless steel centrifugal pumps

 Hygienic centrifugal pump units are great for transferring wine, with the open impeller design easily allowing soft particles to pass through. What’s more, they’re perfect for the food and beverage industry as they incorporate stainless steel for maximum sanitation and cleanliness.

Centrifugal pumps offer wineries very steady and reliable output requiring minimal maintenance. Large centrifugal pumps are particularly well-suited to big jobs like tanker truck loading and unloading, or large scale wine blending.

• Flexible impeller wine pumps

These are a type of positive displacement pump, which can achieve high flow capacity. This type of wine pump can run at different speeds and accommodate differing viscosity types. This pump also offers a gentle pumping action which ensures the consistency of the fluid is unaffected by any shearing forces. These pumps are a popular choice for winemakers given their relatively low cost, versatility and low maintenance requirements.

• Lobe pumps

These are a form of positive displacement pump, specially designed for food processing. In fact, these are the most versatile pumps for winemakers. They’re great for moving solids and must, and have the flexibility to cover other cellar operations like bottling, juice transfer, pump overs and barrel work.

Lobe pumps also enable winemakers to handle liquids of varying viscosities. In addition, the gentle pumping action is great for handling fragile solids and maintaining the integrity of the wine. They can be mounted on a hygienic stainless steel trolley with start/stop and variable speed controls. As well as having anti-corrosion properties, stainless steel is antibacterial too.

• Peristaltic hose pumps

These are a positive displacement type of pump with a gentle pumping action. They can dry run, handle solids, are reversible and offer trolley and different control options. However, they can be an expensive piece of kit, they take up a large amount of space and aren’t as versatile as other pump solutions.

• Air-operated diaphragm pumps

These pumps are a popular choice offering vineyards a leak-free, gentle action pump with the versatility of variable flow and discharge pressures. In addition, they are low cost, low maintenance and have self-priming, dry-running capabilities.

They can also produce a lot of pressure and can be shut off against the pump without damaging any components or equipment. Air-operated diaphragm pumps come in a range of materials including hygienic stainless steel.

What was our specification for this demanding application?

At North Ridge Pumps, we can specify a wide range of pumps for a variety of industrial and commercial applications.

Better still, we’re not limited to a single pump technology. Our expertise enables us to offer a bespoke solution, not something straight off the shelf. So we always select the most cost-effective pump for any particular client, project and application.

Our UK winery client had a very specific set of requirements. So we specified 3 trolley-mounted stainless steel hygienic centrifugal pumps with built-in frequency inverters for speed control. 

These pumps are specifically designed to handle low viscosity liquids during the winemaking process. We manufactured the pumps from full AISI 316 stainless steel with a surface finish rated at 0.8 μm Ra – a very high level of smoothness for exceptional hygiene and easy cleaning.

The pumps were built with DIN11851 DN40 suction and discharge, and had a 1.5Kw motor capable of flows up to 20m³h and 10m head, contained in a shroud for easy cleaning. Each pump unit is also trolley mounted for easy movement all around the winery.

For more information on Winery Pumps: Mobile Hygienic Pumps for Wine Production talk to North Ridge Pumps Ltd