<p>I agree wholeheartedly that the brand of Soya makes all the difference. With Sainsbury's own it doesn't matter if I heat the Soya, cool the coffee, add before or after - it always curdles. At the other end of the scale Lidl's own never curdles. Looking at the ingredients I see Lidl have something called "acid regulator" - heaven knows what that is, but if the acid in the coffee is the problem then the regulator (doing I suppose what the suggested pinch of salt or bicarb does) is the solution.</p>

CC BY-SA 3.0
2016-05-24T06:57:25.897Z
2016-05-26T08:45:57.613Z
2016-05-26T08:45:57.613Z
Robert D
<p>I simply add a pinch of baking soda to a cup of coffee, and the soy milk doesn't curdle. Black coffee has a pH about 5, baking soda around 9, but it buffers the coffee enough that the soy won't curdle.  It works for other curdling plant milks as well, I just prefer the soy.  I do not notice that it changes the flavor, although too much probably would. But you just need a small pinch, smaller than a peppercorn.  Anyone watching their sodium intake should count it.  I read the label on the soy creamer trying to figure out why their product didn't curdle when plain soy milk did, and sodium bicarbonate was the ingredient that made sense. It works hot or cold, but too much in a hot cup of coffee gives a nice fizzing reaction.  A few more bubbles for your froth! </p>

CC BY-SA 4.0
2019-09-22T15:31:38.107Z
Welcome! This is an interesting suggestion! I took the liberty to remove the bit about trying chocolate milk, as it’s not really answering the question (which is a very basic rule here). If you want to learn about about how the site works, I recommend you take the [tour] and browse through our [help].
Stephie
CC BY-SA 4.0
2019-09-22T14:58:05.733Z
2019-09-22T15:27:29.737Z
2019-09-22T15:27:29.737Z
Micki Killoran
<p>I had the problem with soya milk curdling but now find that by adding a little cold water to the coffee before adding the milk generally helps. OK, the coffee's a little cooler but more palatable than with lumpy soya.</p>

CC BY-SA 3.0
2016-08-02T13:29:34.617Z
2016-08-03T06:33:29.280Z
2016-08-03T06:33:29.280Z
Sally
<p>1ml or more of dark/dutched (alkalised) cocoa powder mixed in with the coffee before adding the milk stops it curdling. 0.5ml just about works enough to make it drinkable for me without really affecting the taste although I'm not a coffee expert, don't pay much attention to the taste and there is still a little bit of curdling. I guess either make a mocha or go for the sodium bicarb/less acidic coffee tricks</p>

CC BY-SA 4.0
2022-07-30T20:10:34.060Z
A teaspoon of raw cacao powder works for me, too. This is with Vitasoy Protein Plus which is literally just organic soy beans and water.
Shaun Moss
CC BY-SA 3.0
2017-03-10T21:48:27.843Z
2017-03-10T21:59:24.050Z
2017-03-10T21:59:24.050Z
user4011
<p>I have encountered this problem with Soya Milk for some years, my wife is milk - intolerant.
I make up the coffee and allow it to cool. I store it in the fridge, then add cold Soya Milk to the desired colour, I warm up the ready made drink (NOT TOO HOT)
End of curdling problem provided i don't get it too hot. </p>

CC BY-SA 3.0
2017-08-01T08:20:35.390Z
2017-08-01T08:20:35.390Z
Alec
<p>(1) According to a Kitchn article <a href="http://www.thekitchn.com/why-does-soymilk-curdle-in-hot-148329" rel="nofollow noreferrer">Why Does Soy Milk Curdle In Hot Coffee?</a></p>

<blockquote>
  <p>The two factors behind the curdling of soy milk are <em>acidity</em> and <em>temperature</em>.</p>
</blockquote>

<p>You can <em>reduce the acidity</em> via the <strong>choice of coffee beans, grind size,</strong> and other brewing variations.</p>

<p>You can <em>lower the temperature</em> by <strong>letting the coffee cool</strong> before adding soy milk or <strong>gradually adding the coffee to the soy milk.</strong> The latter cools the coffee with air and with the total mass of cold soy milk, and also reduces the number of soy milk molecules that get heated to the critical temperature by hot coffee.</p>

<p>(2) <strong>Froth the soy milk</strong> before adding the coffee. Frothing in air makes it a nice thermal insulator, increases its surface area, and changes the surface tension. As a result, less if any soy milk will curdle. <a href="https://coffee.stackexchange.com/a/2029/2908">Frothing has additional benefits.</a> A <a href="https://www.google.com/webhp?ie=UTF-8#q=handheld%20milk%20frother&amp;tbm=shop" rel="nofollow noreferrer">hand-held frother</a> works for me.</p>

<p>According to this <a href="http://coffeegeek.com/guides/frothingguide/steamguide" rel="nofollow noreferrer">Milk Frothing Guide</a>,</p>

<blockquote>
  <p>Properly prepared milk is always foamed. Even if you don’t want any foam in the drink you want to foam the milk just slightly. Incorporating air into the milk improves and sweetens the taste. Milk that has not been foamed at all tends to taste flat and dull by comparison.</p>
</blockquote>

<p>(3) Experiment with <strong>different kinds of milk substitutes</strong>. If I recall correctly, coconut milk didn't curdle while hemp milk curdled easily. There's also almond milk, almond-cashew milk, rice milk, hazelnut milk, and oat milk. Hemp milk doesn't froth up very well, at least not the brand I tried.</p>

CC BY-SA 3.0
2016-08-03T22:27:48.463Z
2016-08-03T22:27:48.463Z
2017-04-13T12:51:53.733Z
Jerry101
<p>I had 2 cups of coffee with soy milk the other day. The first cup was delicious. The second cup curdled. I was baffled at first, then realized the 2nd cup was decaf, which is weird, because decaf has less acid. 
So far the soy milk has never curdled with regular coffee, always does with the decaf.</p>

CC BY-SA 4.0
2019-03-25T19:33:51.683Z
2019-03-25T19:33:51.683Z
Kathy Miller
<p>I use Alpro chocolate soy milk. I just add it to hot coffee as usual. Works like a chocolate charm :) </p>

CC BY-SA 4.0
2019-01-02T18:07:22.423Z
2019-01-02T18:07:22.423Z
Pedro
<p>I saw a demonstration where this person added  half sqeezed lemon juice before adding the soy milk, and that balanced the acid levels. Someone one here wrote to add dark cocoa powder mix, prior to adding the soy milk. </p>

CC BY-SA 3.0
2018-01-30T23:43:55.657Z
2018-01-30T23:43:55.657Z
flower
<p>a <strong>tiny bit of bicarbonate soda</strong>  into the black coffee ...then stir fast as you add the soya milk    removes the acidity &amp; stops the curdle  ...enjoy !</p>

CC BY-SA 3.0
2016-03-19T20:30:04.563Z
Interesting. Is it the pH of the bicarb (baking soda) that makes a difference? Or something else? About how much is necessary -- just a pinch, 1mL (1/4 tsp), ...? Does it not taste salty?
hoc_age
CC BY-SA 3.0
2016-03-27T20:26:26.007Z
This is my solution as well. baking soda will bring down the acidity of the coffee which will help prevent curdling. A small pinch is all you need.
meskarune
CC BY-SA 3.0
2016-03-14T12:57:42.877Z
2016-03-14T12:57:42.877Z
user2281
<p>It seems that <em>the cause</em> of the situation of curdling soya milk in coffee is that the acid from the coffee curdles the proteins and/or fats in the (soya or other) milk, being catalysed by the heat of the coffee; so that's what needs to be mitigated.</p>
<p>There are a couple related questions on <a href="http://cooking.stackexchange.com">Cooking.SE</a>, including <a href="https://cooking.stackexchange.com/q/30060/25286">this one</a> that suggests <strong>adding salt to the coffee will help a little</strong> (table salt, or even bicarb / baking soda).
I have tried adding table salt to the coffee first, then adding the coffee to the soya milk, and it seems to help (a little, sometimes; YMMV). <a href="https://cooking.stackexchange.com/q/28179/25286">Another Cooking.SE question</a> also suggests waiting for coffee to cool.</p>
<p>The linked TheKitchn article (linked from the aforementioned previous question and @PythonMaster's answer) suggests that cooling the coffee, or pouring coffee <em>into</em> the soya milk (rather than the other way around) helps via similar mechanisms. In my experience in messing around with this, <strong>I have not found the order of adding ingredients makes much difference</strong> (i.e., putting coffee into the soya milk). <strong>It absolutely depends on the type of coffee</strong>, also, because <a href="http://www.highergroundstrading.com/blog/38/coffee-acidity:-the-science-and-the-experience--" rel="nofollow noreferrer">different coffees will have different degrees of acidity</a>.  See also <a href="http://www.highlandcoffeesbr.com/coffeeprofileschart.php" rel="nofollow noreferrer">this table</a> about relative acidity levels.</p>
<p>However, it is certainly the case that <strong>adding coffee into the milk will be helpful in general</strong> (compare also to <a href="https://cooking.stackexchange.com/q/4208/25286">tempering of eggs</a> or adding acid <em>into</em> water rather than the other way around).  In this order, these allow temperature and acid (respectively) to more slowly come into balance between the two substances as they are being combined.</p>
<p>IMHO, I have found <em>the brand</em> (i.e., the ingredients and production methods) of the soya milk to be the biggest factor. I (personally, with not-entirely-scientific -- yet! -- trials) find that <strong>soya milk brands that contain emulsifiers (or other additives) are less likely to curdle in coffee</strong>.  My only guesses are that</p>
<ul>
<li>these compounds (emulsifiers, thickeners, or stabilisers, such as <a href="http://en.wikipedia.org/wiki/Carrageenan" rel="nofollow noreferrer">carrageenan</a> or <a href="http://en.wikipedia.org/wiki/Xanthan_gum" rel="nofollow noreferrer">xanthan gum</a>) interfere with the coagulation, or</li>
<li>something else in the processing (perhaps, e.g., pasteurisation) has denatured the proteins or otherwise chemically changed the nutrients such that they are less likely (cf., UHT or ultra-pasteurised milk)</li>
</ul>
<p>I generally prefer to avoid the additives, so this is an unfortunate conclusion for me personally.</p>
<p>Freshness of the milk is also an issue; milk of all types will spoil and slowly start to curdle due to natural processes (fermentation, bacteria, other contamination). There's another question <a href="https://cooking.stackexchange.com/q/45476/25286">about storing soya milk in the freezer</a>, where we reached similar conclusions.</p>
<p>At the risk of making this an even longer answer, here are some other things to try:</p>
<ul>
<li>Add <em>cold coffee</em> into soya milk.  Does it curdle?  If so, it seems temperature is not your only enemy.</li>
<li>Check your label; does it have carrageenan or so?  If so, this might not be the metaphorical silver bullet.</li>
</ul>
<p>I'm interested (fascinated, even; obsessed, maybe?:) ) with this, so I'd really like to hear feedback. Of the dozens of articles I've read on this, I've still not found a proper solution.</p>
<p>Happy experimenting; comments welcomed.</p>

CC BY-SA 4.0
2015-02-11T13:46:23.220Z
2022-02-15T13:51:17.283Z
2022-02-15T13:51:17.283Z
hoc_age
<p>Well actually, it depends on how hot your coffee is, not the type of coffee. The acidity in black coffee is higher than the acidity in soy milk, though, and it can act like a coagulant, making like loose tofu in your cup of coffee. The heat of your soy milk can actually <strong><em>HELP</em></strong> curdle the soy milk even more, rather than preventing it. In this <a href="http://www.thekitchn.com/why-does-soymilk-curdle-in-hot-148329" rel="nofollow">food science website</a>, which contains the info I gave, it says:</p>

<blockquote>
  <p>It seems like the best way to prevent curdling is to warm the soy milk slowly by pouring it into the cup first, then gradually add the coffee. Letting the coffee cool a bit before adding soy milk and avoiding more acidic coffee beans may also help.</p>
</blockquote>

<p>This should answer your questions and prevent the curdling in your coffee. I hope this helps you!</p>

CC BY-SA 3.0
2015-02-11T14:03:16.697Z
Do you find that order of combination or temperature works? No doubt that it helps a little, but this doesn't help much, in my experience. Also, *type of coffee absolutely has an effect* on the situation; [different coffees have different acidity](http://www.highlandcoffeesbr.com/coffeeprofileschart.php) and this makes a big difference, in my (admittedly non-scientific) experience.
hoc_age
CC BY-SA 3.0
2015-02-11T22:51:20.920Z
Oh. Well at least this still helps the person asking! :-)
Anthony Pham
CC BY-SA 3.0
2015-02-11T01:16:40.033Z
2015-02-11T19:18:52.033Z
2015-02-11T19:18:52.033Z
Anthony Pham
<p>I like to make a coffee with soya milk. Sometimes when I add the milk to the coffee it curdles, i.e. it separates into lumps floating in translucent liquid. This tastes and looks a bit strange (but is still drinkable).</p>
<p>How can I prevent soya milk from curdling? Does it depend on the type of coffee, or the type of soya milk? Or does it have something to do with how and when they are mixed together?</p>

CC BY-SA 3.0
2015-02-11T01:16:24.527Z
You mean soy milk right?
Anthony Pham
CC BY-SA 3.0
2015-02-11T01:30:13.153Z
Soya milk is the UK name for soy milk, so yes.
vclaw
CC BY-SA 3.0
2015-02-11T13:51:17.017Z
Great topic. Several related questions on [cooking.se], including [this one](http://cooking.stackexchange.com/q/30060/25286) and [this one](http://cooking.stackexchange.com/q/28179/25286)  about salt, temperature, etc. Expanded in [my answer](http://coffee.stackexchange.com/a/430/262) below.
hoc_age
CC BY-SA 4.0
2021-06-17T23:58:38.607Z
Just got a tip from a barista, though it goes a bit against the conventional advice below, but can confirm it works! (sample size 1):

Pour the coffee into the milk BEFORE frothing.
matt
<milk><soy-milk>
How to avoid soya milk curdling in coffee?
vclaw
# How to avoid soya milk curdling in coffee?

(Asked by: username_0 on 2015-02-11)

I like to make a coffee with soya milk. Sometimes when I add the milk to the coffee it curdles, i.e. it separates into lumps floating in translucent liquid. This tastes and looks a bit strange (but is still drinkable).

How can I prevent soya milk from curdling? Does it depend on the type of coffee, or the type of soya milk? Or does it have something to do with how and when they are mixed together?

**Tags:** milk, soy-milk

> **Comments:**
> **username_1**: You mean soy milk right?  
> **username_0**: Soya milk is the UK name for soy milk, so yes.  
> **username_2**: Great topic. Several related questions on [cooking.se], including [this one](http://cooking.stackexchange.com/q/30060/25286) and [this one](http://cooking.stackexchange.com/q/28179/25286)  about salt, temperature, etc. Expanded in [my answer](http://coffee.stackexchange.com/a/430/262) below.  
> **username_3**: Just got a tip from a barista, though it goes a bit against the conventional advice below, but can confirm it works! (sample size 1):  Pour the coffee into the milk BEFORE frothing.  

---

## 12 answers

### Answer by username_2 on 2015-02-11. Score: 13

It seems that *the cause* of the situation of curdling soya milk in coffee is that the acid from the coffee curdles the proteins and/or fats in the (soya or other) milk, being catalysed by the heat of the coffee; so that's what needs to be mitigated.

There are a couple related questions on [Cooking.SE](http://cooking.stackexchange.com), including [this one](https://cooking.stackexchange.com/q/30060/25286) that suggests **adding salt to the coffee will help a little** (table salt, or even bicarb / baking soda).
I have tried adding table salt to the coffee first, then adding the coffee to the soya milk, and it seems to help (a little, sometimes; YMMV). [Another Cooking.SE question](https://cooking.stackexchange.com/q/28179/25286) also suggests waiting for coffee to cool.

The linked TheKitchn article (linked from the aforementioned previous question and @PythonMaster's answer) suggests that cooling the coffee, or pouring coffee *into* the soya milk (rather than the other way around) helps via similar mechanisms. In my experience in messing around with this, **I have not found the order of adding ingredients makes much difference** (i.e., putting coffee into the soya milk). **It absolutely depends on the type of coffee**, also, because [different coffees will have different degrees of acidity](http://www.highergroundstrading.com/blog/38/coffee-acidity:-the-science-and-the-experience--). See also [this table](http://www.highlandcoffeesbr.com/coffeeprofileschart.php) about relative acidity levels.

However, it is certainly the case that **adding coffee into the milk will be helpful in general** (compare also to [tempering of eggs](https://cooking.stackexchange.com/q/4208/25286) or adding acid *into* water rather than the other way around). In this order, these allow temperature and acid (respectively) to more slowly come into balance between the two substances as they are being combined.

IMHO, I have found *the brand* (i.e., the ingredients and production methods) of the soya milk to be the biggest factor. I (personally, with not-entirely-scientific -- yet! -- trials) find that **soya milk brands that contain emulsifiers (or other additives) are less likely to curdle in coffee**. My only guesses are that

* these compounds (emulsifiers, thickeners, or stabilisers, such as [carrageenan](http://en.wikipedia.org/wiki/Carrageenan) or [xanthan gum](http://en.wikipedia.org/wiki/Xanthan_gum)) interfere with the coagulation, or
* something else in the processing (perhaps, e.g., pasteurisation) has denatured the proteins or otherwise chemically changed the nutrients such that they are less likely (cf., UHT or ultra-pasteurised milk)

I generally prefer to avoid the additives, so this is an unfortunate conclusion for me personally.

Freshness of the milk is also an issue; milk of all types will spoil and slowly start to curdle due to natural processes (fermentation, bacteria, other contamination). There's another question [about storing soya milk in the freezer](https://cooking.stackexchange.com/q/45476/25286), where we reached similar conclusions.

At the risk of making this an even longer answer, here are some other things to try:

* Add *cold coffee* into soya milk. Does it curdle? If so, it seems temperature is not your only enemy.
* Check your label; does it have carrageenan or so? If so, this might not be the metaphorical silver bullet.

I'm interested (fascinated, even; obsessed, maybe?:) ) with this, so I'd really like to hear feedback. Of the dozens of articles I've read on this, I've still not found a proper solution.

Happy experimenting; comments welcomed.


---

### Answer by username_1 on 2015-02-11. Score: 7

Well actually, it depends on how hot your coffee is, not the type of coffee. The acidity in black coffee is higher than the acidity in soy milk, though, and it can act like a coagulant, making like loose tofu in your cup of coffee. The heat of your soy milk can actually ***HELP*** curdle the soy milk even more, rather than preventing it. In this [food science website](http://www.thekitchn.com/why-does-soymilk-curdle-in-hot-148329), which contains the info I gave, it says:

> It seems like the best way to prevent curdling is to warm the soy milk slowly by pouring it into the cup first, then gradually add the coffee. Letting the coffee cool a bit before adding soy milk and avoiding more acidic coffee beans may also help.

This should answer your questions and prevent the curdling in your coffee. I hope this helps you!

> **Comments:**
> **username_2**: Do you find that order of combination or temperature works? No doubt that it helps a little, but this doesn't help much, in my experience. Also, *type of coffee absolutely has an effect* on the situation; [different coffees have different acidity](http://www.highlandcoffeesbr.com/coffeeprofileschart.php) and this makes a big difference, in my (admittedly non-scientific) experience.  
> **username_1**: Oh. Well at least this still helps the person asking! :-)  

---

### Answer by username_15 on 2016-03-14. Score: 6

a **tiny bit of bicarbonate soda** into the black coffee ...then stir fast as you add the soya milk removes the acidity & stops the curdle ...enjoy !

> **Comments:**
> **username_2**: Interesting. Is it the pH of the bicarb (baking soda) that makes a difference? Or something else? About how much is necessary -- just a pinch, 1mL (1/4 tsp), ...? Does it not taste salty?  
> **username_16**: This is my solution as well. baking soda will bring down the acidity of the coffee which will help prevent curdling. A small pinch is all you need.  

---

### Answer by username_4 on 2016-05-24. Score: 4

I agree wholeheartedly that the brand of Soya makes all the difference. With Sainsbury's own it doesn't username_3er if I heat the Soya, cool the coffee, add before or after - it always curdles. At the other end of the scale Lidl's own never curdles. Looking at the ingredients I see Lidl have something called "acid regulator" - heaven knows what that is, but if the acid in the coffee is the problem then the regulator (doing I suppose what the suggested pinch of salt or bicarb does) is the solution.


---

### Answer by username_5 on 2019-09-22. Score: 3

I simply add a pinch of baking soda to a cup of coffee, and the soy milk doesn't curdle. Black coffee has a pH about 5, baking soda around 9, but it buffers the coffee enough that the soy won't curdle. It works for other curdling plant milks as well, I just prefer the soy. I do not notice that it changes the flavor, although too much probably would. But you just need a small pinch, smaller than a peppercorn. Anyone watching their sodium intake should count it. I read the label on the soy creamer trying to figure out why their product didn't curdle when plain soy milk did, and sodium bicarbonate was the ingredient that made sense. It works hot or cold, but too much in a hot cup of coffee gives a nice fizzing reaction. A few more bubbles for your froth!

> **Comments:**
> **username_6**: Welcome! This is an interesting suggestion! I took the liberty to remove the bit about trying chocolate milk, as it’s not really answering the question (which is a very basic rule here). If you want to learn about about how the site works, I recommend you take the [tour] and browse through our [help].  

---

### Answer by username_7 on 2016-08-02. Score: 3

I had the problem with soya milk curdling but now find that by adding a little cold water to the coffee before adding the milk generally helps. OK, the coffee's a little cooler but more palatable than with lumpy soya.


---

### Answer by username_8 on 2017-03-10. Score: 2

1ml or more of dark/dutched (alkalised) cocoa powder mixed in with the coffee before adding the milk stops it curdling. 0.5ml just about works enough to make it drinkable for me without really affecting the taste although I'm not a coffee expert, don't pay much attention to the taste and there is still a little bit of curdling. I guess either make a mocha or go for the sodium bicarb/less acidic coffee tricks

> **Comments:**
> **username_9**: A teaspoon of raw cacao powder works for me, too. This is with Vitasoy Protein Plus which is literally just organic soy beans and water.  

---

### Answer by username_10 on 2017-08-01. Score: 2

I have encountered this problem with Soya Milk for some years, my wife is milk - intolerant.
I make up the coffee and allow it to cool. I store it in the fridge, then add cold Soya Milk to the desired colour, I warm up the ready made drink (NOT TOO HOT)
End of curdling problem provided i don't get it too hot.


---

### Answer by username_11 on 2016-08-03. Score: 1

(1) According to a Kitchn article [Why Does Soy Milk Curdle In Hot Coffee?](http://www.thekitchn.com/why-does-soymilk-curdle-in-hot-148329)

> The two factors behind the curdling of soy milk are *acidity* and *temperature*.

You can *reduce the acidity* via the **choice of coffee beans, grind size,** and other brewing variations.

You can *lower the temperature* by **letting the coffee cool** before adding soy milk or **gradually adding the coffee to the soy milk.** The latter cools the coffee with air and with the total mass of cold soy milk, and also reduces the number of soy milk molecules that get heated to the critical temperature by hot coffee.

(2) **Froth the soy milk** before adding the coffee. Frothing in air makes it a nice thermal insulator, increases its surface area, and changes the surface tension. As a result, less if any soy milk will curdle. [Frothing has additional benefits.](https://coffee.stackexchange.com/a/2029/2908) A [hand-held frother](https://www.google.com/webhp?ie=UTF-8#q=handheld%20milk%20frother&tbm=shop) works for me.

According to this [Milk Frothing Guide](http://coffeegeek.com/guides/frothingguide/steamguide),

> Properly prepared milk is always foamed. Even if you don’t want any foam in the drink you want to foam the milk just slightly. Incorporating air into the milk improves and sweetens the taste. Milk that has not been foamed at all tends to taste flat and dull by comparison.

(3) Experiment with **different kinds of milk substitutes**. If I recall correctly, coconut milk didn't curdle while hemp milk curdled easily. There's also almond milk, almond-cashew milk, rice milk, hazelnut milk, and oat milk. Hemp milk doesn't froth up very well, at least not the brand I tried.


---

### Answer by username_12 on 2019-03-25. Score: 1

I had 2 cups of coffee with soy milk the other day. The first cup was delicious. The second cup curdled. I was baffled at first, then realized the 2nd cup was decaf, which is weird, because decaf has less acid.
So far the soy milk has never curdled with regular coffee, always does with the decaf.


---

### Answer by username_13 on 2019-01-02. Score: 0

I use Alpro chocolate soy milk. I just add it to hot coffee as usual. Works like a chocolate charm :)


---

### Answer by username_14 on 2018-01-30. Score: 0

I saw a demonstration where this person added half sqeezed lemon juice before adding the soy milk, and that balanced the acid levels. Someone one here wrote to add dark cocoa powder mix, prior to adding the soy milk.


---

