Why boil starters for 15mins?

[Gnomebrewer]

I'm sitting here bored while my yeast starter is boiling, and it got me thinking. Why does it need to be boiled for 15mins? Every set of instructions for making a starter says to boil for this long, but why? Surely it would all be sterile with a 5min boil. Is there something else the boil needs to do?

 

[armedcor]

I've always done 5 minutes max...Haven't had any problems!

 

[max384]

Personally I think it's just an overabundance of caution. I only bring mine to a boil for a minute or two, with no disastrous effects. As long as you practice good sanitation you should be okay.

Basically, there's no harm in instructing people to be extra cautious about avoiding infections...

 

[Gnomebrewer]

THanks for the replies. 5min boils from now on!

 

[Bobby_M]

I barely boil. Including the water heating, it goes into the shop microwave for 5 minutes.

 

[Takuie]

I too rarely boil. I asked this question myself a while back and did a little research. Basically, 5 minute boil kills bacteria and whatnot, 15 minutes boils out chlorine and other minerals out of tap water. IMHO, mineral-less water is not so good for yeast.

Personal experience, liquid courage and the ability to sacrifice a precious batch of delicately harvested yeast one day wanted to see how it would turn out if I didn't boil. Tossed water in microwave for 2-3 minutes, cooled and added yeast. Did this 4 batches in a row and never had any problems, actually seemed like my yeast took off quicker.

If boiling makes you happy, by all means do it. My friend uses just warm tap water and he has had zero problems.

 

[WoodlandBrew]

If you use bottled water and DME directly from the manufacturers bag there is no need to boil. The manufacturing processes are quite sanitary.

 

[gwapogorilla]

15 minutes is waaaaay overdoing it. Personally, I boil for about 2 minutes. It's just a precaution to make sure the wort mixture is sterile.

 

[Yesfan]

I've been doing the 15 minute boils too, but after this thread no more. Could I use the filtered water coming out of my fridge? Do I still need to boil it or could I nuke the wort for 1-2 minutes in the microwave?


On another note, how much DME do you use per pint of water? Seems everyone is different about how much DME to water you use. The last starter, I used a cup of DME to 4 cups of water and boiled for 15 minutes. Thought I would ask if there's a better "rule of thumb" to keep from wasting DME or making your starters too big/little for some batches.

 

[Darwin18]

I used to do the 15 boil, but now I just bring it up to a quick boil before I cool and pitch my yeast. The 15 minutes is an overabundance of caution and it gets repeated over and over again.

 

[Takuie]

When I do make a starter from scratch, I find getting my wort for my starters around 1.040 seems to be a good medium starting point for me. Since I brew 3 common recipes the most, I harvest the yeast and leave enough of the liquid that I don't bother adding anything. Just pull from fridge, set till room temp, toss in a tablespoon of DME and let 'er rip on the stir plate until pitching time.

 

[Brew_G]

Yesfan...for a standard starter, 100g of DME per 1L of water (basically a 1/10 ratio of DME to water) is a good rule of thumb. Ideally you'd go off mass rather than volume measurements for DME, but if you go by volume (e.g. cups), then it seems yours was overdone. For 4 cups, you'd probably want about 6.5 tbsp of DME.

 

[WoodlandBrew]

Could I use the filtered water coming out of my fridge?

Water filters can harbor bacteria. I wouldn't trust it.

Do I still need to boil it or could I nuke the wort for 1-2 minutes in the microwave?

It's actually the heat from the microwave that kills organisms, not the radiation, so if you got it up to a boil in the microwave that would be fine.

On another note, how much DME do you use per pint of water?

100g (3.5oz) of DME and 1000ml of water (32oz) seems to be quite common. It's really the amount of DME that drives the yield, not the volume. Biomass yield is 0.1g of yeast for every gram of sugar and there are 20 billion cells per gram. DME is 75% fermentable so that means 100g of DME will yield 150 billion cells. (It's not as complicated as the calculators may make it look) The rate at which this happens depends on temperature and agitation method. See this calculator:

http://www.woodlandbrew.com/2015/02/starter-calculator.html

 

[Braufessor]

I buy my DME in a 3lb bag.....so, once it is open and exposed to the air, I worry that it could harbor something I don't want. I keep in in a 1 gallon ziplock, but...... still. The 3lb bag might be open for a month or more worth of starters. I boil about 12 minutes or so. I am usually doing some other brew related stuff at the time, so not a big deal to take a few more minutes "just in case."

 

[cannman]

Thinking of beer as a food, I'm pretty sure we're going after the denaturing of Clostridium botulinum toxins. While the spores that give rise to the organism producing Botulism will survive, the toxic nature of its enzyme can be denatured in 10 minutes at standard atmospheric pressure. High enough IBUs should keep the spores in check once bottled...

http://edis.ifas.ufl.edu/fs104

 

[max384]

Thinking of beer as a food, I'm pretty sure we're going after the denaturing of Clostridium botulinum toxins. While the spores that give rise to the organism producing Botulism will survive, the toxic nature of its enzyme can be denatured in 10 minutes at standard atmospheric pressure. High enough IBUs should keep the spores in check once bottled...

http://edis.ifas.ufl.edu/fs104

You won't find C. botulinum toxins in DME. All spores would have been killed and the toxins denatured during the manufacture of DME. During storage, DME is far too dry for C. botulinum to take hold. No need to worry about botulism when dealing with dry malt extract.

 

[brewfarmDan]

I put the DME in a clean flask then pour in boiling water swirl it and cover, then start cooling after 5 minutes. 1.75 oz DME for 600 ML water