The science of loading a front loader washing machine ⚖️

In my early days on the admin team, my evenings on the couch were accompanied by a rhythmic clicking sound that looped every 30 seconds or so. I didn’t realise how odd that was until one time my husband asked what I had been watching all this time. I was in fact scrutinising the circular movement of laundry inside a front loader, trying to help members diagnose and troubleshoot their wash routines. We were taught to check for suds, to track a nappy’s movement within the load, to evaluate where the centre of rotation was and how much it moved. We were chasing the perfect main wash loading.

~ Aurelia, Facebook group admin since early 2020

Gone are the days where we obsess over loading in order to achieve a good clean. We know better now. Loading is important as part of the cleaning factors, but there is a much broader range in which stains and soiling can still be effectively removed than you might expect.

A lot of our earlier front loader advice took ideas that were relevant in top loaders and shoehorned them into a front loader. This is true for loading, extended dry pailing, spin speed and item size. It’s been a long road unpicking this, especially loading. So we’re here to bust our own myth today.

How did we end up here?

The Clean Cloth Nappies Facebook group started way back in 2015. The original admin team met in a North American Facebook cloth diaper group, Fluff Love University, and decided to create an Australian- and NZ-focused group. We took their existing guidance and advice and started adapting it to Australian and NZ conditions. Today, our advice differs from Fluff Love on many things.

Almost all misunderstandings around loading trace back to a single unverified sentence on the Fluff Love website, on a page that has sat untouched for the last decade.

Enter the cleaning factors

Loading is one of the four cleaning factors: time, temperature, chemicals (detergent and stain removers) and mechanical action (loading).

Before the whole team learned about and understood the cleaning factors, we mistakenly put too much weight on the importance of loading. However, as our experience and understanding of how front loaders work has deepened, we’ve had to correct our course. There is now more nuance in all aspects of our advice.

The lowdown on mechanical action

When it comes to loading, top loaders are more particular. Top loaders rely on the mechanical movement of the drums, fins, or discs to create torque in the fabric–water suspension and shear force between the fabrics. In other words, the twisting motion inside a top loading washer tub causes garments to slide past and rub against each other to create the mechanical action required to clean the items.

Not enough water, and the mechanical forces cannot be efficiently transmitted throughout the load. Too much water, and the fabrics can’t come in contact enough. The right water-to-fabric ratio (aka loading) is thus very important in top loaders.

Front loaders operate on a completely different mechanical principle. As the drum turns, clothes are lifted and then fall back down, a physical process that happens regardless of whether the machine is fully loaded or running light. The impact created by the fabrics hitting the drum as they fall is what provides the agitation for cleaning.

The results show that the textiles experience the greatest mechanical action upon impact after having been projected into the air by the motion of the rotating drum, and as textile loading increases, the free-fall velocity and deceleration upon impact of the textiles decreases, leading to less mechanical action in the impact region of the drum.

~ Mac Namara et al. (2012), “Dynamics of textile motion in a front-loading domestic washing machine,” in Chemical Engineering Science, 75, 14-27.

Of course, it is more economical in terms of water and electricity to run fuller loads, but that doesn’t mean it is necessary to get a decent clean. Gravity still exists inside a front loader whether a machine is one-third full, half full or three-quarters full. As long as the other cleaning factors are present, your items will get clean even in a smaller load. 

It is important to know that smaller laundry loads can lead to changes to the remaining cleaning factors.

The time component: when your machine adjusts the cycle length

Almost all front loaders weigh the load and adjust the water level accordingly. Many also reduce the time of a fully rated Cotton cycle if the machine is half full or less. Some brands are more particular in what they consider ‘full’ (Samsung machines in particular often have very narrow definitions of fullness). 

Across most machines, the best main wash cycle is an extended Cotton cycle. Sometimes this drop in cycle time tempts people to switch to another cycle. However, not every cycle in your machine is robust enough to clean soiling and urine out of multi-layered inserts, and not every cycle is weighted for the full capacity of your machine. 

If your Cotton cycle repeatedly drops time, consider pushing your main wash back a day, or adding more items to the machine. Our general guidance is to stick to items that are 60cm x 60cm; but this is more of a precaution for top loader users. In a top loader, larger items can twist together and ball up, causing problems during the wash and spin phases. Front loaders don’t have the same issue with items balling up, so you can wash larger items like adult t-shirts, sweatshirts, towels and flat single bed sheets. 

🚨 Avoid washing fitted sheets as nappies can become trapped inside, reducing agitation and washing poorly.

The chemical factor: matching detergent dose to load size

A half-full load of laundry does not need as much detergent as a full load of laundry. If you are washing fewer items, decrease the detergent to match.

In the past, we gave underloaded washes too much credit for causing excess suds. In reality, excess suds are a mismatch in soiling level and the detergent type or volume.

If you add a full dose of detergent into a small load of laundry, your machine might generate so many suds that it goes into a suds lock. This can also happen in soft water when using a detergent or stain remover that contains a high percentage of water softening agents. 

Front loaders will sense the lingering suds during the cycle and incorporate extra rinse phases or extend the cycle duration to ensure all the surfactant residue is thoroughly flushed away. If your washing machine does not do that automatically, you can add an extra rinse cycle yourself.

We know it’s not always possible to gauge how much detergent you need. If you end up with a suds explosion and need to quell a whiteout mid-cycle, mix a small amount of hair conditioner or standard fabric softener with water, and slowly pour it down the detergent drawer. The anti-foaming agents and cationic surfactants will rapidly neutralise and collapse the excess bubbles.

Excess suds and agitation

The biggest misunderstanding with excess suds is that they will somehow inhibit agitation. That is another mini-myth from the Fluff Love era, and one you might hear repeated in other cloth communities. Remember, gravity is always present inside a front loader, and clothing, sheets and towels will always weigh more than the suds.

Excess suds can get messy, but they never have enough buoyancy to cancel out gravity.

Overloading is still a no-no

While parts of the cloth community worried about whether their machine was too empty, many people inadvertently added too many items to their wash. Overloading, not underloading, is what actually ruins your wash. 

The middle of the drum receives little to no agitation. Scientists call it a ‘dead zone’.

Finally, a dead zone region has been identified near the axis of rotation of the drum, where textiles can become trapped for up to 30 s and experience less mechanical action than textiles closer to the rotating drum wall undergoing higher velocity free-fall tumbles.

~ Mac Namara et al. (2012)

Stuffing ‘just one more thing’ until your machine is tightly packed means more items will be inside this dead zone, resulting in insufficient agitation and poor cleaning results. It also prevents other items from tumbling properly inside the drum.

Overloading also adds extra strain to the various components of your front loader. It increases wear and tear on the drain pump, motor, and control assembly, and may cause premature failure of the bearings.

If a front loader is overloaded, small items can get trapped in the door too. We occasionally hear from members who have had their PUL shells rip in the door this way.

All things considered, we’d say it’s better to underload than to overload your machine.

Myth busted 👊💥

If the science is so conclusive, what makes loading myths so sticky? It is partly because of how often the myth is repeated in cloth nappy Facebook groups and laundry-focused lifestyle pieces from Better Homes & Gardens and Yahoo News. The other reason is because of the domino effects it has on other cleaning factors. 

A full, but not overloaded, wash is the most resource-efficient option. However, if you want to run a half-full main wash, go for it. Just adjust your detergent dose accordingly; you won’t need a 9kg heavily soiled dose of detergent if the machine is half full.

Don’t stress about loading in your front loader. With the right combination of cleaning factors your nappies will still get clean in an underloaded cycle.