Thursday, September 5, 2013

The Essential Flourless Mustard Sauce (recipe from Masterchef Australia)

So this recipe comes courtesy of Heston Blumenthal’s relatively recent appearance on Masterchef Australia. I don’t usually watch MasterChef. I find the competitive-but-not-seemingly-fair reality TV nature of it all bugs me. But then they had “Heston week” so I (of course) watched that.
The recipe is available here.

Heston talks in various places about using agar agar as a thickening agent rather than flour, so that you get a “cleaner” flavour. This recipe is one he demonstrated on the show, so I thought I’d give it a try with our roast chicken dinner this week.


1.       Reduce wine
2.       Cook in the other liquids
3.       Add the agar agar and cook
4.       Mix through the mustards & herbs, blend
5.       Heat & serve
(Very simple as far as these things go).

Reduce the wine

Now previously, I’ve commented on not finding it easy to tell when you have reduced your liquid sufficiently – like in this case, to reduce it to one third. This time I came up with a good solution. (And if anyone is thinking “well, obviously…” I apologise, but I can’t be the only person who didn’t think of this straight off). Once you pour in the liquid, measure the depth with something – I used a fork. Take note of the depth. 
Then, once you reduce it, you now have something to compare it against by dipping it in again. Easy. (Note the slightly more yellow colour of the reduced liquid. Because otherwise, you see, these photos look identical. They aren't. You'll have to just trust me.)

Cook in the other liquids

In goes the chicken stock…
And the milk and cream.
That gets boiled for 10 minutes.

Add the agar agar

Then the agar agar gets added, and whisked in.
Then simmered for 4 minutes, and left to cool slightly.

Then, blended with a stick blender to ensure there aren’t any lumps of agar agar in the sauce. Even though mine didn’t seem to have any lumps, it did still seem to improve the silkiness. 

Add the mustard & herbs

In goes the mustards, and the herbs. Smells pretty good. But seems fairly thick. White sauce thick, so probably OK, I think...

Then, heat and serve!


So the taste was fine. And when the sauce was piping hot, it was OK, if a little thick.
But. Once the sauce hit anything cool (like say, the dinner plate) or when it cooled off (like when you were half way through eating) it turned to jelly.
Cold, creamy mustard flavoured jelly. It didn’t taste bad, it was just too odd – off putting to eat and too thick.

I leaves me wondering if either :
a) my agar agar is unusually strong? (I’ve looked online, and there is nothing to suggest that agar agar varies in strength), or
b) Heston simply includes way too much agar agar in his dishes.

This is the second time I’ve felt that the agar agar thickening was too strong – I found the same issue with the beetroot lollies. (insert link).


The flavour was nice enough, but the very thick & jellied result on cooling was off putting – unpleasantly so. I am considering trying this again with ¼ the recommended agar agar. Or, possibly, borrowing some agar agar off a friend (different brand) and then doing a test with equivalent amounts in liquid to check the result.

Has anyone else had issues with using agar agar as specified in a Heston dish? I’d love to know if you have used it either way.

Next: Not sure! Don't have any plans for once... Suggestions?


  1. Awesome write up!

    As soon as we saw this we had to give it a go (helped that we had all the ingredients to hand).

    I writing this comment sat in front of a plate of JELLIED SAUCE FLAKES. It is like something from a HP Lovecraft story.

    Just finished the write up as part of a tribute post to your very fine blogging. Should be up in next couple of days.

    Suggestion for the next recipe? You Do now have a rep for tackling all the toughest recipes from H@H, so I reckon the Pressed Apple dessert thingy should be your next target.

    Or, with spring on the way in your hemisphere, I recommend that pea risotto, if you saw it. I don't really like risottos but I *loved* that.

  2. Hey c'mon! Don't leave us on our own here. Looking forward to seeing what you've got lined up next with spring on it;s way. Hope you guys are still having fun in the kitchen

  3. I found a conversion table flakes to powder ( It suggests a 1:6 ratio. So your 1/4 is probably still overstated.

  4. in the show i think he allowed it to set and then blended it to a sauce again, he then said it wouldn't set again after it had been blended with a hand blender

    1. exactly, he let it set in the fridge until it looked like a piece of rubber, then blended it. It works perfectly fine that way.

  5. Other than possibly overdoing the agar-agar in the conversion of flakes to powder (bugger! completely reasonable mistake), I'm pretty sure you're supposed to let it cool and set, and THEN stick blend it, so that it breaks up all the long chains of proteins and turns into a fluid gel, rather than a block of wobbly jelly. That's certainly how I remember him doing it, anyway.

  6. I know this is a delayed response to this, but I have only just discovered this blog. As the last two comments mention, you should allow the sauce to cool - it then becomes a gel. Then, using a hand blender, blend the gel to turn it back into a fluid. Then you can warm it up again. I was lucky enough to get the Modernist Cuisine at Home book recently and it has a whole section on fluid gels that covers this, including how much agar agar you should use for different consistencies. It's really small, e.g. 1g of agar agar for about 100g of liquid will get you a very thick consistency for a sauce.

  7. Hi. I watched Heston and actually you made one mistake. Once he boiled agar agar, he cooled it in the fridge and then blended. After blending he've put it on the heat, added mustard and other ingredients and said that even if it cools down again it's not gonna go jelly.