More Yeast Starter Questions

[GrimyHoboSack]

I'm doing a yeast starter for the first time for a brew and I have a few questions. I'm doing a step up starter, I did a 1.8L starter and then just moved it up to a 3.6 or so starter last night.

When measuring a starters size do you go off of the size of the liquid or the liquid+DME?

How much headspace do you usually leave in a starter? My first starter didn't have a huge krausen and was fine in with 200ml of headspace, but my current 3.6L starter in a 4L flask has a huge krausen and was starting to spill out when I woke up this morning.

I decanted my first starter, swirled the remaining liquid and then threw the rest on astir plate to get the yeast back into suspension for pouring. When I went to pour the yeast in there were still some decent sized whitish chunks at the bottom. I got as many as I could in thinking there was probably yeast there, but is that likely to be break material or something I can leave out or am I right in pitching as much as possible?

I sampled some of the decanted liquid from my first starter and it tasted undrinkably abysmal, that's normal for a starter and doubly for a lager starter fermented at room temp? I've heard starters contribute off flavors, but I 'm not sure just how bad it's supposed to be.

 

[jfowler1]

When measuring a starters size do you go off of the size of the liquid or the liquid+DME?

from http://www.mrmalty.com/starter_faq.htm

"When making starter wort, keep the starting gravity between 1.030 and 1.040 (7 - 10°P). You do not want to make a high gravity starter to grow yeast. As a ballpark measurement, use about 6 ounces (by weight) of DME to 2 quarts of water. If you're working in metric, it couldn't be easier. Use a 10 to 1 ratio. Add 1 gram of DME for every 10 ml of final volume. (If you're making a 2 liter starter, add water to 200 grams of DME until you have 2 liters total.) Add ¼ teaspoon of yeast nutrient, boil 15 minutes, cool, and add yeast."

Take this as you want, because I think it reads both ways. In one sentence, it sounds like the 1 gram DME : 10 ml is for post boil (ie - final volume)....

"Add 1 gram of DME for every 10 ml of final volume."

....and the next sentence sounds like it is supposed to be the volume of liquid + DME pre-boil.

"If you're making a 2 liter starter, add water to 200 grams of DME until you have 2 liters total"

So I honestly don't know. However, the evaporation you see over a 15 minute gentle boil is not going to concentrate your wort so much that it should make a big difference. 1.030 - 1.040 is a pretty forgiving range. Personally (for a 1 liter starter), I weight 100 grams of DME in a sauce pan, and measure 1000 ml seperately in my 2000 ml flask. I then pour the liquid into the pan to bring up to a boil, so my total starting volume is 100 grams DME + 1000 ml of liquid (essentially less concentrated than if you made 1 liter = DME + Liquid).

I only do it this way because it makes measurements a little easier, and I like to start the boil in a sauce pan to break up clumps and reduce boil over issues, then transfer to the flask for a 15 minute boil.

Honestly, I would also love to know the correct answer, but either way - close enough.

As far as head space, I really like using the 2000 ml flask for my 1 liter starters. I always try to keep my starter around 1 liter, and just change the number of vials, rather than always using one vial, and changing the amount of wort. The slider tool at mrmalty.com is great for that calculation. I use a stir plate, so I am able to get away with this strategy. I also do the starter about 24 hours ahead of pitching, so rather than cool and decant, I just pitch the whole thing. That would not be such a great idea with a 1+ gallon (grown up from one vial) starter going into 5 Gallons of Munich Helles.

Just my thoughts.

Joe

 

[GrimyHoboSack]

Thanks for the response.

I've been boiling straight in the flask to reduce the amount of sterilization necessary and to cut down on chances for infection. I didn't keep too close of an eye on the before and after volume, but it seems that the shape of the flasks prevents most of the boil off that occurs in a regular pot.

The first starter I tried mixing in the flask and that was a bit of a trial, so the second starter I whisked the DME and some water in a bowl then poured it into the flask to boil it. That worked out much better and since it takes much less water to whisk with I can do that then fill the starter up to the desired amount more accurately.