Comparison of Steam Tips

The milk lineup used for the test

I been wondering how different milk types would react, when exposed to the hot steam coming from different holed steam tips - therefore I´d put up a "little" research within the area, where I would examine how easy the combination of a specific steam tip and milk is to froth, but also how long time it will take and finally a summarize of the frothed milk. 

The general idea is to expose the twenty different combinations to one frothing attempt each, where I will judge/comment on that, therefore my skills within frothing is somehow crucial for all of the milks and steam tips try-outs. The single try-out per combination is set, because it will then be a more uneven result and therefore more interesting - in other words I won't give each combinations, many try-outs before I hit the optimal frothed milk possible for each combination.

I listed the different combinations below;

1. Two hole tip - skimmed milk (A - 0,1% fat)
2. Two hole tip - skimmed milk (B - 0,5% fat)
3. Two hole tip - low-fat milk (C - 1,5% fat)
4. Two hole tip - low-fat milk (C - 1,5% fat)
5. Two hole tip - whole milk (E - 3,5% fat) 

6. Three hole tip - skimmed milk (A - 0,1% fat)
7. Three hole tip - skimmed milk (B - 0,5% fat)
8. Three hole tip - low-fat milk (C - 1,5% fat)
9. Three hole tip - low-fat milk (C - 1,5% fat)
10. Three hole tip - whole milk (E - 3,5% fat) 

11. Four hole tip (standard) - skimmed milk (A - 0,1% fat)
12. Four hole tip (standard) - skimmed milk (B - 0,5% fat)
13. Four hole tip (standard) - low-fat milk (C - 1,5% fat)
14. Four hole tip (standard) - low-fat milk (C - 1,5% fat)
15. Four hole tip (standard) - whole milk (E - 3,5% fat) 

16. Four hole tip (special) - skimmed milk (A - 0,1% fat)
17. Four hole tip (special) - skimmed milk (B - 0,5% fat)
18. Four hole tip (special) - low-fat milk (C - 1,5% fat)
19. Four hole tip (special) - low-fat milk (C - 1,5% fat)
20. Four hole tip (special) - whole milk (E - 3,5% fat)

* The special four hole tip is the one with a centered hole and three in the outer ring.

The different milk types; A = skimmed milk, B = skimmed milk, C = low-fat milk, D = Barista milk, E = Whole milk

The different milk types shown above, is primary the drinking assortment from the biggest nordic supplier called Arla, and delivers milk with a fat percent from 0,1% to 3,5% - the developed Latte Art milk is not buyable in every grocery store, but I took it along to see if their experimenting has a proving point. The general lineup from Arla is off 1 l. per milk and consist of homogenized and pasteurized milk, where the Latte Art milk isn't pasteurized but instead highly homogenized. 

Latte Art (D) milk info

The special Latte Art milk has been developed in cooperation with some of the worlds best Baristas. The secret behind the milk is that Arla enriches the milk with its own naturally fat proteins. This provides the milk with the best assumptions to create a soft and velvety foam, that highlights the notes of the coffee. The Latte Art milk is targeted towards any espresso based drink, such as Caffe Latte, Cappuccino and Macchiato. 

The accessories pack of Rocket steam tips

Steam tip info

Rocket have produced  an upgrade kit for their Rocket Espresso machines and fit able for some other produced espresso machines, where you will receive four different designed steam tips, shown in the above picture. This will let you experiment with different frothing techniques, because they will stretch and create a whirlpool in the milk by their own different way. This set is containing a two hole tip, a three hole tip, a standard four hole tip and a four hole tip with three holes in the outer ring and one centered - all this is purchasable for the price of 250 DKK ($42). 

How to attach the different steam tips?

1.Unscrew the standard steam tip

2. Choose which steam tip you want to put in place, swap out the o-ring, and screw it on 

          3. Experiment!

The two hole tip

Two hole tip

The two hole steam tip is what I along with the one hole steam tip, consider to be the starter tip, because it gives you the biggest window of operating your milk correct. With that I mean that the two holes limits the outgoing steam and therefore will the milk be heated a bit slower, which gives you more time to incorporate air into the milk.  

In difference to the single tip solution, the two hole tip is dividing the pitcher up into two areas, which each will have its own "whirlpool". Note the above left picture that shows the flow from a side view - the two hole tip lets the steam escape from these holes, which will push the milk, that the steam wand is mired in. This will create a downforce upon the milk, which will lead the milk towards the bottom of the pitcher and when its reaches - it will bounce backwards towards the surface, where it will be pushed downwards again. This is in other words a whirlpool, where you are able to work the entire milk - meaning you can incorporate air into the entire milk instead of creating a fat top foam layer. 

The three hole tip

Three hole steam tip

The next level of steam tips will be the three holed tip, which will deliver a faster result comparing to the previous described two and single hole tips. The result is quicker delivered, because their will be a more concentrated merging between the hot steam and milk due to the three holes increased limit of exit steam. This will heat the milk faster and therefore also minimize your window of stretching the milk, which is leading this steam tip for more advanced use.

Note the above right picture of the three zones created by the three holed steam tip, which is causing more activity within the milk and therefore a quicker micro foam result. Likewise the quicker result, the steam tip also incorporates air into the milk a lot quicker than the previous steam tips - therefore if you are used to operate with these tips, then slowing down to a two or single hole tip will seem like going from a speedboat to a rowboat.  

The traditional four hole tip

Traditional four hole steam tip

The four hole tip is often represented in the most coffee cafes and is therefore thought off as a professional steam tip - this is because its currently the quickest steam tip at the market, that also can deliver the maximum result of great micro foam. Comparing this specific steam tip along with the previous tips, the speed of the four hole will shine through when frothing for more than one cup of cappuccino. Don't get me wrong, because the steam tip will also be extremely quick when frothing for a single cup - but those people who froth a single cup are they truly seeking a quicker frothing? Im an egotist kind of guy when it comes to coffee and Im always preparing a cup of coffee for myself and therefore my needs for the quickness are relatively low - but when matching result with the other steam tips, I always get the best micro foam result from this one.

The above right picture reveals the four whirlpool zones created by the four hole steam tip, which activates the entire milk within the pitcher - leaving it to heat very quickly. The four hole tip is very aggressive when it comes to letting maximum hot steam out in the pitcher, therefore it isn't preferable if you have a relatively small espresso machine, like the Francis Francis X1 or a Rancilio Silvia, because it will invalidate the steam capacity before you have finish your frothing, leaving a very inconsistent steam power. BUT if your machine possesses the steam capacity than the four tip is always to be preferred, because the activity in the pitcher created by this steam tip, will allow perfect tiny air bobbles incorporated into the milk.

The four hole tip, with a centered hole and three in the outer ring

Special four hole steam tip
This included steam tip in the steam tip pack from Rocket is untraditional, because its a four hole steam tip with a center hole and three in the outer ring of the tip. I haven´t tried it yet, even though I have got one, simply because I can't seem to found out how it can be logically good when frothing milk? More of that below the attached picture - but i theory it would be as aggressive as a normal four hole steam tip and therefore also non-preferable when having a small espresso machine like described before.

The three zones that will be created by this steam tip is equal to the three hole tip, but the center hole will beside these three areas, push the milk downwards and thereby create resistance in the three areas (In my mind). I will try it below and comment if this will be my new favorite steam tip or it will be kept hidden once more.

Steam tip result
The result of the steam tip testing is listed in the above chart, where the frothing time is giving per. combination as well as the difficulty attached to it. The results were supportive of my previous assumptions regarding the increased speed of frothing when using more steaming holes - in other words the frothing is much faster when using a steam tip that allows more hot steam to merge with the milk. I found the standard four hole tip very useful when chasing the lowest amount of time spent on frothing - but the special four hole tip weren´t as quick as the standard, which impressed me a lot.

With that said, speed isn't everything, especially not when the primary focus is upon taste and quality - like mine is. I don't really give a .... if it takes 20 sec. or 10 sec. as long as I get the best/optimal result. So which steam tip would I use myself? Hmm, well I honestly have been using the standard four hole tip for a week by now and I´ve got to know it better than the rest of the steam tips pack - but I'm actually most joyful upon the three hole tip, because it gave me the best velvety results.

I blame it on the time, because I have been practicing with the four hole tip and therefore is used to its quickness of frothing, but with the three hole tip I got those extra seconds, where I could fine-tune my technique and create a bit more richer, smooth and velvety micro foam. This test where also performed with a 0,35 l. pitcher, which is kind of small when using a four hole tip, so I would properly use the four hole tip when frothing in a 0,6 l., 0,75 l. or 1,0 l. pitcher - nevertheless its always nice to have the option to change around a bit.

* I would like to comment especially on the special four hole tip, because I was not very pleased with it during this test, because it sprayed milk out of the pitcher and also created some very big bobbles, when the whirlpools conflicted with each other. Therefore Im certain that I´ll never use this steam tip again and due to that it will be the worst steam tip choice of the pack.

What does very easy, easy, medium and hard mean?

1. Very Easy - the best possible condition when frothing milk, even a newborn coffee enthusiast will not experience any kind of trouble in the pursuit of great micro foam. The milk merging with the hot steam in the pitcher just flows with each other and you are left only to control the steam handle.
2. Easy - its no big deal frothing milk and if you want to produce some excellent frothed milk in front of your friends, then nothing will stop you. This level doesn't require much experience when frothing milk, just the basics about when to stretch the milk and stop heating it.
3. Medium - The milk can be a challenge, but if you have patience and focus you´ll get the job done perfectly. This level requires some attention in the frothing action and is therefore not a simple job, if you want to be rewarded with the perfect micro foam.
4. Hard - The hunt after the perfect micro foam is long gone and you have to struggle to get a decent result. This levels requires every aspect of your concentration and the possibility of failure is greater than success. 

Choice of milk result
I can honestly say that between these five chosen milks lays a huge difference in taste and frothing ability - take for example the skimmed milk with 0,1% of fat, this milk separated when being frothed, leaving a very poor result when poured into the cup. This meaning that the skimmed milk at 0,1% is already out of the competition before is really started, because it was the only that separated, was thin tasting. The second skimmed milk with 0,5% fat were a bit easier to frothed and had some great quality such as great sweetness, thickness and excellent bobbles, but it were lacking when it came to support the coffee flavors and keeping a great depth in flavor.

The whole milk was honestly the most easy milk to get some great frothing results with, but the fat taste of cream affected the final cup a bit too much, to make it the best pick. Therefore was the five milks cut down to two, where they actually did great both. I couldn't really tell them apart, so I would go for the low-fat milk, because it has better options for purchase than the special developed Barista milk.

A final note within the frothing area would be, that frothing the milk actually became more successful when giving the steam tips with more holes, because of the greater steam power and hereby action within the pitcher. The air simply became better incorporated in the milk comparing to the two holed tip for example.

I now this have been an extremely long article and I could have divided it in two or three parts, but I thought it would be interesting reading for you guys, so I wouldn't have you all waiting for the other parts. Hope you enjoyed this review and thereby create your own opinions :)

The Rocket Evoluzione v2 also did magnificent doing these tests, because it just frothed all these milk test without even a single drop in steam capacity even once. Im truly glad for this wonderful machine, its just keep impressing me and increasing my passion for coffee, quality coffee.

// Hendrup

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