Earlier this week, I was invited to Google headquarters in Mountain View. The mothership is made of many small buildings and within one of them, there’s a teaching kitchen where Googlers may take cooking classes. I came to do a special ChefTalk on pho and Chef Dede Sampson and her team made samples from The Pho Cookbook.
Before my presentation began, Googlers were buying up the book and perusing it. By the time I finished, there were great questions, things that I’ve pondered as I’ve stood over the stove looking at my stockpot. Figuring that you may have similar questions, I’m sharing a synopsis of our conversation. Of course, if you have extra info or experiences to add, we’re all eyes and ears here at VWK.
When can you boil pho broth? A lot of people say that boiling pho broth is no bueno. That’s true for when you’re doing a long simmer to make from-scratch broth in a conventional stockpot (in a pressure cooker, the broth never boils). During the long cooking of a traditional pot of pho, if there’s prolonged vigorous boiling, the impurities get suspended into the broth, which then makes the pho broth very cloudy and taste slightly off, sometimes a bit dirty.
To remove most of the impurities, I do an initial parboiling of the bones (vegetable pho does not suffer from much scum). It seems fussy but totally reduces the likelihood of impurities hanging around in your pho pot. You bring the bones to a vigorous boil to release the scum. A gentle simmer (bubbles steadily percolating at the top) ensures some fat enriches the broth but not a ton, which would weigh the broth down and make it no so pho-ish.
Regardless of pho cooking method or whether your pho features animal or vegetables, there’s always boiling happening when you’re heating up the broth. You’re aiming to get the broth nice and hot before you ladle it over your assembled bowls so it may warm up all the other ingredients! Sometimes, if your broth yield is too high (aim to match the broth yields in my recipes), you may boil the strained broth down to concentrate its flavor.
In summary, boiling can help but also hinder the making of good pho broth. Know when to boil to your advantage.
Is cloudy pho broth evil? Not necessarily, especially when you consider that the starches in the noodles naturally turn the broth cloudy once you stir up your bowl at the table. Ideally, when the pho bowl is set down in front of you, what you’re looking at does not look like dirty dishwater. When a pho shop serves up that kind of bowl, it’s likely toward the end of service when the broth is at the bottom of the pot. Pho shops often dilute and blend their broth so maybe something got into the broth that usually does not. I’ve experienced more good than bad pho at my favorite pho shops so I try to give them a break.
Sometimes, however, the cloudiness can’t be helped. I found that out with turkey pho that I made for ChefSteps. I was confounded for weeks by the cloudy, yucky broth. Straining multiple times through cloth, coffee filters, and then adding egg whites and other methods didn’t make a huge impact.
I asked a very seasoned German-born professional chef what his turkey stock was like and he said, it’s always cloudy. But then I realized that the solution was to rinse the turkey carcass and spray the impurities off. The fat in the roasted bird still caused some cloudiness but the flavor was much brighter. You’ll see a note in the rotisserie chicken pho recipe (page 82 of the Pho book) about the slight cloudiness.
Cloudy pho broth happens. It doesn’t mean the soup is inedible. I slurp it up and look forward to the next bowl.
Should pho spices be toasted? Not always. When I make quick pho or pho in the pressure cooker, I toast the spices in the pot before adding other ingredients. That helps to release the flavors and natural oils in the spices. But for the traditional long simmer, the spices sit in the pot for hours so they will release their essences over time. I used to toast the spices for all pho but found that it doesn’t make a huge difference in a traditional stockpot
When I got a little pho lesson in Hanoi, the cook added the spices toward the end and toasted her spices. If you like to toast your spices all the time, there’s nothing wrong with doing it.
Pho varies from cook to cook. You can blend your own pho spices as I suggested. You should also develop your own technique (read this newspaper story about Chau Du’s Portland, Maine, pho shop). What’s important is you have a firm foundation to cook from.