Yeast starter question
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Nateo
Well-Known Member
Stirplate isn't necessary. Just pitching yeast into wort will grow more cells. Stirplates just increase the number of cells you can grow for a given volume of wort. Intermittent shaking of the starter would work fine.
Golddiggie
Well-Known Member
You can make a starter without a stirplate. BUT using a stirplate lets you make smaller starters to get your target yeast cell count. They also finish in far less time on a stirplate (under 24 hours on a stirplate).
One thing common to all starters. DO NOT fit it with an airlock. Use sanitized foil or a foam stopper instead (especially with a flask). You want to have gas exchange, not just vent CO2 as produced. It needs to pull in air/oxygen too.
One thing common to all starters. DO NOT fit it with an airlock. Use sanitized foil or a foam stopper instead (especially with a flask). You want to have gas exchange, not just vent CO2 as produced. It needs to pull in air/oxygen too.
Most of what I know of yeast starters, I learned here:
http://www.mrmalty.com/pitching.php
Definitely worth a read. The general idea is that you want to pitch your liquid yeast into a very low gravity wort, perhaps 1.020, and introduce oxygen so that they will multiply. When I make them, I add 10 g of DME for every liter of final volume that I want and add it to an Erlenmeyer flask. Then, I just fill with tap water until I reach my final volume, boil it, and then cover with foil while it cools. I also sanitize the flask before I add anything to it and I flame the top before I pitch the yeast from the vial or the smack pack. Both White Labs and Wyeast claim that their yeast packages have enough cells, but many (including myself) do not agree.
There are other details like temperature and timing that you should also control for, so I'd really recommend reading through that article - about halfway down, there is a really good description of how and when to make your starter.
Two things. First, constant stirring keeps the yeast in suspension and prevents them from flocculating, so you will wind up with a higher number of yeast for a given starter volume. Second, it ensures that you are constantly introducing oxygen to the wort, which enables more reproduction. I have yet to build myself a stir plate, so I just shake my starter vigorously at the beginning and as often as I can while it grows. This means I need to make bigger starters than someone that is constantly stirring. That website I linked earlier has a calculator that allows you to determine the size of starter you need to make in order to get to an appropriate pitching rate.
Hope this helps - starters are really easy to make and will really up your brewing results. People pitch the yeast directly from the vial or the smack pack all the time and claim to have no problems, which is probably true. But their results probably aren't as good as they could be.
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Ok, so I made my first starter.
Wyeast 1099 whitbread smackpack
1 liter water
1/2 cup dme
Sanitized everything and put it in a growler covered it with foil.
Swirled the growler by hand.
Upon waking the next morning the yeast look to have fallen out of suspension like it should look after cold crashing in the fridge. Looks like I have a small yeast cake on the bottom. I have been swirling gently for 2 days.
Should the yeast fall to the bottom if there is no swirling?
When I swirl it after I get up in the morning the yeast seem to be in little chunks till I get it stirred up. Is that normal?
I will post a pic when I get home tonight.
Wyeast 1099 whitbread smackpack
1 liter water
1/2 cup dme
Sanitized everything and put it in a growler covered it with foil.
Swirled the growler by hand.
Upon waking the next morning the yeast look to have fallen out of suspension like it should look after cold crashing in the fridge. Looks like I have a small yeast cake on the bottom. I have been swirling gently for 2 days.
Should the yeast fall to the bottom if there is no swirling?
When I swirl it after I get up in the morning the yeast seem to be in little chunks till I get it stirred up. Is that normal?
I will post a pic when I get home tonight.
Depending on how flocculant the strain is, many yeasts will start to settle quite quickly -- for example, my Wyeast 2112 starter showed visible settling in just 20 minutes this morning after I decanted and brought the yeast back into suspension in the remaining wort.
Similarly, the "chunks" can be very normal as well; again, that's part of flocculation. Your goal in swirling is to simply to keep as much yeast in suspension -- and, by extension, increasing the surface area exposure of wort to yeast -- to encourage cell growth. Sounds like you're on the right track!
Similarly, the "chunks" can be very normal as well; again, that's part of flocculation. Your goal in swirling is to simply to keep as much yeast in suspension -- and, by extension, increasing the surface area exposure of wort to yeast -- to encourage cell growth. Sounds like you're on the right track!
Gameface
Well-Known Member
I have been using 1oz (by weight) of DME for every 200mL of water. Am I using too much DME? I've had good results, but don't want to use more DME than I have to and don't want to stress the yeast.
You're using WAY less DME than I am. I don't take hydro reading on my starters and got my ratio of DME to water from some random website with a pictorial on making a starter.
Gameface,
That works out to about 14g of DME per 100ml of water -- a bit more than most will be using. Generally you'll use approximately 1g DME per 10ml of water to give you a ~1.040 wort.
www.yeastcalc.com has a great DME calculator for starters, in addition to being a bit more flexible than Jamil's calc.
EDIT: gmcastil's post mentions 1.020 wort; my understanding is that many will use 1.020 to "wake up" or start growing cells that have been collected from adverse conditions (harvested from a bottle, for example.) Generally that's done in steps; a smaller 1.020 wort in the first step to begin cell growth, then stepping up to a 1.040 wort to "kick it into high gear." Incidentally, the math for your 1.020 wort is just as simple: 1g DME per 20ml water. However, when making a starter from a new vial, smackpack or other healthy source, 1.040 wort seems to be commonly accepted as the best practice.
That works out to about 14g of DME per 100ml of water -- a bit more than most will be using. Generally you'll use approximately 1g DME per 10ml of water to give you a ~1.040 wort.
www.yeastcalc.com has a great DME calculator for starters, in addition to being a bit more flexible than Jamil's calc.
EDIT: gmcastil's post mentions 1.020 wort; my understanding is that many will use 1.020 to "wake up" or start growing cells that have been collected from adverse conditions (harvested from a bottle, for example.) Generally that's done in steps; a smaller 1.020 wort in the first step to begin cell growth, then stepping up to a 1.040 wort to "kick it into high gear." Incidentally, the math for your 1.020 wort is just as simple: 1g DME per 20ml water. However, when making a starter from a new vial, smackpack or other healthy source, 1.040 wort seems to be commonly accepted as the best practice.
As I mentioned in my post, I learned most of what I know about yeast starters from reading Mr Malty. If 1.040 is a better choice for starter wort, then that's great to know - perhaps I've been under pitching?
EDIT: I went and re-read the section on Mr Malty about making starters and apparently, the 1g DME per 10mL of final solution leads to a wort with a gravity between 1.030 and 1.040, which is what Geordan had stated. I have no idea where my statement about 1.020 came from - ignore it, but follow the instructions about the ratio of DME to final solution. That's what you want.
