Why do we boil yeast starter wort?

[MGamber]

I was recently reading something here where someone mentioned that DME has already been boiled and doesn't need to be sanitized. Given that it's probably packed under sanitized conditions in a bag that nothing is going to get into and RO water has nothing in it (and tap water is pretty sanitary), why do we bother boiling a yeast starter? Could I just sanitize the pot I'll be using, mix DME into RO water and make sure it's all dissolved, dump it in a flask and add the yeast? That would save the forever it takes to get it to a boil and the even longer to get it back down to a pitchable temp. Thoughts?

 

[MaxStout]

It takes maybe 5 minutes to bring it to a boil in a saucepan, and maybe 10 minutes for me to cool the flask to pitching temp in an ice bath. Fifteen minutes added to my process is trivial for the peace of mind knowing my starter wort is sanitary.

BTW, never assume tap water is sanitary. Unscrew the screen from one of your faucets and have a look some time.

 

[MGamber]

I do a 1.5 liter starter and it takes forever to bring that to a boil and then another forever to cool it down. It's a pain in the ass. I don't assume tap water is sanitary (or there'd be a lot of dead people) but I do use RO water since the salts are already in DME, also. It'd be nice to make an hour (at least) long chore into a 10 minute process. So...any reason why it has to be boiled?

 

[day_trippr]

I never boil starter wort. I do bring the water to a boil with 1-3 drops of Fermcap depending on starter size, put the pot in the sink, carefully add the prescribed amount of DME and a dab of yeast nutrient, give it a stir, put the lid on, and start filling the sink with cold water.

Best as I can tell from reading about pasteurization vs temperature vs duration there's nothing that prolonged boiling is going to add to that sanitation regimen...

Cheers!

 

[brewcat]

I bet you could get by without boiling. Only one way to find out...

I buy big bags of dme. So wouldn't necessarily be sanitary the next time it is used.

How does it take so long to bring to a boil? Put a lid on it. Boil for a minute. I do hate cooling down. But again, put a lid on it and set it aside.

 

[Gnomebrewer]

Have you ever made a pre-hopped extract kit batch of beer?
Mix the tin of pre-hopped liquid extract, maybe add some sugar and/or DME and/or Maltodextrin.
Add tap water. Mix. Add yeast.
It's not boiled. It's not pasteurised. We assume that the high dose of yeast will out-compete the low dose of undesirable microbes. My father-in-law has been making the same beer this way (Coopers lager) every second week for as long as I've known him and not had infections.
For a starter you would probably be OK. But remember that you are multiplying whatever is in there - that could mean growing bacterial/bad yeast numbers as well. Also, there are no hops in the starter to help prevent infection. I still boil my starters.

 

[madscientist451]

I don't boil DME starter wort. Heating to 180F is good enough. I usually get busy and it goes above that, but if you feel like you need to boil it, go ahead.

 

[mongoose33]

You want to speed up the boil? Put that water in the microwave and get it boiling. It's only a liter.

 

[MaxStout]

So...any reason why it has to be boiled?

Technically, you don't need to boil the wort. Just bring the water to a high enough temp to kill most pathogens that could contaminate the wort, ~180F or so. Heat the water, add DME, chill to pitch temp. This should shave some time off your process.

 

[Jtk78]

I do a 1.5 liter starter and it takes forever to bring that to a boil and then another forever to cool it down. It's a pain in the ass. I don't assume tap water is sanitary (or there'd be a lot of dead people) but I do use RO water since the salts are already in DME, also. It'd be nice to make an hour (at least) long chore into a 10 minute process. So...any reason why it has to be boiled?

What are you boiling on that it takes forever to boil 1.5L of water? I do starters in the garage as well as brewing. I have a single electric burner. I may or may not have bypassed the thermostat on mine, but it boils pretty quickly

 

[BarleyStanding]

I've used bottled water and DME without a boil a few times, when I was in a time pinch, without any negative consequences. My guess is that it's mainly a sterilization step that's been passed down as "Brewing Canon". I still boil my starters and I find it much easier to get the DME into solution with hot water (no clumps and doughballs). If you do add the DME to boiling wort, make sure and turn off the burner and give it a minute, otherwise you will have wort all over the place (did that once, only once).