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​The Curdle Hurdle.

​The Curdle Hurdle.

Posted by Fergus on 4th Oct 2019

The great curdle hurdle, we’ve all been there, you go to pour a nice soy latte only to be confronted by a white blob for latte art and a drink that resembles a glass of tofu rather than coffee. The rise in popularity of non dairy milks has been meteoric in the last few years, and whilst this has been great for customers who don’t drink dairy, it has presented a whole new challenge for baristas, how to overcome the curdle hurdle…

Why do alt milks curdle?

There are two main factors that cause alternative milks to curdles when introduced to coffee, acidity and temperature. Coffee is more acidic than alternative milks, so when we add them together the acids in the coffee cause the proteins in the alt milk to coagulate, giving us that rather unpleasant ‘tofu’ effect. This is then exacerbated by heat, which increases the speed of acid induced coagulation, the hotter the milk is steamed the faster it coagulates when introduced to the coffee, there is a sweet spot between 50-60 degrees, so aim for that.

How can we combat the curdle?

Baristas are a canny lot and a number of ‘workarounds’ have been developed over the years to combat this problem, I want to show you my two favorite ways stop the tofu and get over the curdle hurdle.

Keep it cool, pour it fast, no art no worries:

This method is probably the most straightforward workaround, all you have to do is make sure you don’t heat the alt milk past 60 degrees, preferably between 50-55, then pour nice and fast into the cup, don’t worry about the latte art, the goal here is texture, just before the top stop your pour and then pour a little heart on top, or forget about the art altogether and just pour it to the top. By keeping that temperature low and combining the milk with the coffee rapidly you avoid the big chunky tofu texture.

The bicarb solution solution:

This is my favourite, but involves a little science and a little prep. Grab a dropper bottle from the pharmacy so you can be precise, some bi-carb soda and scales.

What we are going to do is change the pH of the coffee by using a bi-carb solution. By adding 1-2ml of bi-carb we will raise the coffee’s pH and reduce its acidity, helping the alt milk to not coagulate upon contact. 

Using a ratio of 1g bi-carb to 20g of warm water, mix up a solution in dropper bottle. You can also use a jar and a pipette to dose the solution into your espresso.

 Once it has all dissolved add 1-2ml to your espresso. 

You will notice the crema react to the bicarb, almost like it ‘blooms’ give it a good swirl. 


The idea here is to only raise the pH a little, and not impact the flavour or quality of the espresso. Steam your alt milk and pour, you should find it similar to pouring regular milk

Whilst the bicarb solution is great it is important not to add too much of the solution or you will end up giving the coffee a salty or mineral flavour, one or two drops should be fine, a tell tale sign you have added too much is if you notice a strange salty smell. Find a bottle that has a nice small spout to help combat this.

Not all alt milks are created equal.

Soy, almond, coconut, macadamia, rice, oat, cashew, the list of alt milks seems to grow longer and longer with each passing year, and which alternative options you choose for your customers is up to you, however I recommend reading the ingredients list, many alt milks contain oils, thickening agents, (starches, carrageenan, or vegetable gums), flavourings and syrup sweeteners, it is always good to know what you are serving your customers, so do your research.

Alternative milks are here to stay, so master them.

Anyone who has worked in coffee for ten years or more remembers a simpler time when the only non dairy option was soy, those days are gone and now the consumer has a plethora of options in how to get their coffee fix without a dairy hit. We need to be able to provide those customers with the same experience and satisfaction that dairy drinkers get. So stop serving curdled tofu coffee and overcome the curdle hurdle!