# 靜置是必須的嗎?

頻道:現代主義烹調作者、肥鴨餐廳研發

{%youtube pYA8H8KaLNg %}

## 關於靜置
常看到的觀點認為
肌肉纖維在加熱後會產生不可逆的收縮 但冷卻後仍然會恢復一定的伸縮

作者認為這觀點毫無道理 烹調後肌肉組織損失的水分 是不可逆的

:::info
:::spoiler
Sure,meat shrinks as it's heated, but juices don't move around inside the meat, because water isn't compressible and there aren't tunnels within the meat where it can flow freely.
Only juices very close to the surface can percolate out and into the pan where they sizzle and boil away.
Eventually that sizzle slows as juices more than a few millimeters beneath the crust struggle to reach the surface and as the meat rests, juices aren't sloshing around being reabsorbed like a sponge.

Yes, some moisture will slowly wick into the dry crust or crispy skin, and this usually isn't a good thing, but any juice that leaked out during cooking is gone forever.

There are a bunch of pseudoscientific explanations of resting floating around. And my friend Meathead Goldwyn at amazingribs.com has a great article reviewing them and debunking them one by one.

n "Modernist Cuisine", I hypothesize that as meat cools proteins dissolved into the juices begin to thicken in gel, making the juices more viscous, so they don't spill out when you slice into the meat.
We used a fancy viscometer to show that juices go thicken as the meat rests. but if you've ever refrigerated stock, you already know it thickens in gels.
Duh! It's also irrelevant unless your meat is cold enough for gelatin to gel.

I'm embarrassed to say, we overlook an incredibly obvious and simple explanation for why juices leak out of meat and why resting doesn't matter.

Here's a simple demonstration. This pot of water is 210 degrees Fahrenheit(100c), around the temperature of meat, just beneath a ripping hot seared crust.
This is a pipette. Think of it as a muscle fiber filled with water and protein. When I release my hold on the suction bulb, the steam pressure immediately squirts water out the open end of the tube.
Now watch what happens as I steadily drop the water temperature to 130deg f(54c), as if we're moving towards the medium-rare core of the steak. At any temperature, there is always some water evaporating the steam, which creates vapor pressure and at the temperatures within a warm steak, these pressures are enough that when you slice into the meat, rested or not, you're creating new escape routes for the juices near the cut surface to be forced out.
So unless you enjoy a cold steak, your only choice is whether you want the juices to end up on the cutting board or the plate.

This surprised me. These were not the results I was expecting, but I've repeated my experiments and each time I get the same result.
So, how do I explain why scientifically minded cooks, like Kenji lopez-Alt, Dan Souza at ATK, Dr. Greg Blonder at Amazing Ribs have found that rested meat retains slightly more juice.
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[Resting Meat: Why I Think It Is A Mistake, and Why I think Holding Some Meat Is A Good Idea](
https://amazingribs.com/more-technique-and-science/more-cooking-science/science-of-resting-meat/ )

在充分休息後使其達到130f(54c)
透過切開時擦去桌上流失的水分來計算損失

在這裡作者認為是否休息 並沒有差別 那麼為什麼還要靜置?

作者認為靜置對於血水保留並沒有幫助，並提及他在書中對於靜置的錯誤，「肉類烹調後蛋白質膠冷卻凝固會保留水分」，實際上要透過凝膠保留水分早就太冷了。

而常見到的觀點認為「肌肉纖維在加熱後會產生不可逆的收縮，但冷卻後仍然會恢復一定的伸縮」，這種海綿論點也不是實際情況，流失的水分並不會被吸回去。且引用了amazingribs的review說明測試情況。

不過，確實有些水分會慢慢滲入乾皮或脆皮中，但這並不是好事，會影響脆殼


血水多寡的實際的原因是在溫度較高的情況切開，內部蒸汽的壓力會把這些水分推出來，讓你感覺好像流失了，而靜置後感覺血水流出較少，只是因為溫度變低蒸氣壓力比較小，流得比較慢而已，但這些汁液本身早就因為烹調而損失，如果想要保留這些肉汁，在餐盤上切會是較好的選擇。

結論是Rests唯一的意義就是讓熱傳到到中心，一到想要的熟度後馬上切開，使多餘的熱快速散掉，而保留血水這個觀點並不是真的