Milk Punch: Science and Practice
December 05, 2016
My first story for Cook's Science is online and boy is it a doozy! I spoke with more than a dozen bartenders to find out how they made their Milk Punch - and it turns out there are a lot of variations and contrasting opinions on how to to do. Hot or cold milk? How much acid is needed? What is the best way to strain it? Is high-fat milk better than low fat?
Milk Punch, as you may know, is a method of clarifying and preserving a punch by curdling it with milk and stringing the curds, so that it's shelf-stable in a cool environment.
They way Cook's Science works is that I did the initial research - talking to all the bartenders - and then their test kitchen tests the theories and tries to figure out the best practical way to achieve great drinks in as much of a controlled environment as they can make. They came up with some interesting confirmations and refutations of bartender Milk Punch lore.
Trying to write about the actual science of it was really challenging, and for that I relied heavy on Dave Arnold's Liquid Intelligence and Harold McGee's On Food and Cooking. I think I understand why milk punch is a clarification method well enough, but honestly I'd love to narrow down why exactly it preserves citrus too.
Anyway, I hope you enjoy the story. It was a big effort and a delight to write.
Great article. How long does it normally take the punches to drain through the coffee filters?
Posted by: Bo | December 07, 2016 at 08:24 AM
That would be a question to put on the Cook's Science website or Dan Souza's Twitter @testcook as he is the one who did the testing portion. I'm curious as to the answer too...
Posted by: Camper English | December 07, 2016 at 09:42 AM
Here's the reply I got from Dan:
It will depend a bit on your coffee filter but 2 to 3 hours for it filter through. And if you get a great product after the first filter you can skip the second.
Also, depending the size of your coffee filter you may need to split the batch between 2, which will speed things up as well.
Posted by: Bo | December 12, 2016 at 01:09 PM
Thank you for the follow-up!
Posted by: Camper English | December 12, 2016 at 01:11 PM
Any idea what this does to the alcohol content of the drink? Is it the same or reduced?
Posted by: Matt | October 24, 2018 at 04:19 PM
Good question. The clarification process should theoretically not remove any alcohol from the drink as it's filtering out solids, but I would imagine just from a liquid loss perspective it would reduce the alcohol content only slightly.
Posted by: Camper English | October 24, 2018 at 06:44 PM
Hello Camper.
I hope it is ok that I write you here!
I have a question regarding milkwashing / Milk Punch.
While I understand why milkwashing will “soften” the harsh flavors of spirits with the removal of polyphenols etc.
What I have a harder time wrapping my head around is how you will get lemon (or lime etc.) in a cocktail to last “for months or years” as I have seen described frequently. That is, I don’t get the science behind it…
As I understand citric acid is a natural conservative and sugar and alcohol obviously is as well.
To specify I have made this bottled drink;
50 ml. Coconut infused Dill Aquavit
10 ml. Regular Carraway Aquavit
20 ml. Fresh Lemon Juice
8 ml. Simple Syrup (1,75-1)
25 ml. Water
And milkwashed it with wholemilk. (4-1).
How come it’s shelflife is so long? Is it because the natural yeasts / Pathogens / Bacteria in the Lemon is filtered off? Or something else?
All the best and thank you in advance!
Regards
Nicolas
Posted by: Nicolas | March 02, 2020 at 02:03 AM
I saw that you got your answer on the Facebook forum so no need for my response!
Posted by: Camper English | March 02, 2020 at 12:46 PM
Hello Camper
I searched a lot about the science behind the long shelflife of milk punches, but couldn't find it... basically the same question Nicolas asked above...can you please tell me if there is any article about it?
thank you in advance!
Regards
Arthur
Posted by: Arthur Ferreira | August 10, 2020 at 05:00 AM
I found the answer - this comes from a smart person in response to Nicolas' inquiry in a FB group:
1) A lower pH is typically less hospitable to most types of pathogens that would cause spoilage
2) The combination of sugar and alcohol reduces water activity (the amount of water available to potential pathogens)
3) The milk washing process strips away most of the proteins and other solids (the curdling of the milk traps solids), leaving less food for pathogens and less proteins that can denature and become rancid.
So in summary it's not just that the juice is preserved, it's that in combination with the alcohol/sugar, plus taking out all the solids.
Posted by: Camper | August 15, 2020 at 11:38 AM
Thanks for sharing the shelf life information. Does anyone have a time frame for the shelf life?
Posted by: Todd Chinnock | September 21, 2020 at 11:39 AM
@Todd - Kept refrigerated, I've seen some as old as a year (back in the 1700s, probably longer than that and kept at cellar temperature). However I'm not sure how good they'll be after a long time. In the ones I've done, after a week or two some stuff comes out of solution and is brownish; worth refiltering to keep it fresh, but if you have to do that a few times that seems like not the point of all this.
Posted by: Camper English | September 23, 2020 at 08:14 AM
I've had a bottle of clarified punch in my fridge for about a year now. It's gotten better with age if anything, and still perfectly clear. I've done another one that had coconut cream in it (very fatty) that lost clarity after a few weeks, but remained delicious. I believe part of it is about what the cocktail is made of, and whether or not you cold crash it (like in beer making) before straining.
Posted by: MattyJ | October 11, 2021 at 11:53 PM
When you clarified the one that lasted a long time (referring to the “cold crashing” part of what you said - not really sure what you mean)
what was the length of time you let it curdle? The one you said “got better with age” piques my interest too. I’ve seen some information about aging milk punches as well.
Posted by: Sam | March 12, 2023 at 11:47 PM