Basic Dry Yeast Questions

[hlm123]

1. Say I use half a pack of dry yeast. How would I store the remainder of it? Is just bundling it back up with a rubber band and sticking in the freezer good? Is it important to keep the outside (and inside) of the packet sterilized throughout the process? I don't have much of a sense of how infections happen. If you stick an unwashed, let's say relatively filthy finger into a packet of dry yeast, does it contaminate the whole pack?

2. For rehydrating yeast, let's say I heat some water in a bowl in the microwave and pour the yeast into that, or pour that into a flask. Is there any real risk of an infection in this process, or would I need to sterilize the bowl and water and everything else?

3. I have a hunch that the answer is no but can or does Star San harm yeast in any way?

 

[flars]

1. Say I use half a pack of dry yeast. How would I store the remainder of it? Is just bundling it back up with a rubber band and sticking in the freezer good? Is it important to keep the outside (and inside) of the packet sterilized throughout the process? I don't have much of a sense of how infections happen. If you stick an unwashed, let's say relatively filthy finger into a packet of dry yeast, does it contaminate the whole pack?

Clip the corner of the yeast packet to pour out what you need. Fold it over and seal with a paper clip or binder clip. Refrigerate in a zip lock bag with the air squeezed out.

One dry yeast manufacturer recommends using the yeast within a week. My bread yeast is in a jar and used over a period of two to three months.

Be as sanitary as possible. Dip hands, scissors, and yeast pack in Starsan solution. Proceed when not dripping wet anymore.

Contaminants can be floating in the air on dust particles. Don't go Howard Hughes though. There is a point of diminishing returns with sanitation.


2. For rehydrating yeast, let's say I heat some water in a bowl in the microwave and pour the yeast into that, or pour that into a flask. Is there any real risk of an infection in this process, or would I need to sterilize the bowl and water and everything else?

You're going to kill your yeast. Use 2 cups of water, without chlorine and not through a water softener, heated to 80°F. Sprinkle yeast on top, stir in after 5 minutes, let sit for up to 30 minutes before pitching. Here is a link to the Fermentis site; http://www.fermentis.com/brewing/homebrewing/product-range/

3. I have a hunch that the answer is no but can or does Star San harm yeast in any way?

Yes, Starsan can damage yeast. Having just some bubbles in your container is not a problem.

Happy New Year Brewing.

 

[BigFloyd]

I'm confused.

Why would you need/want to pour the rehydrated yeast from a bowl into a flask?

Are you wanting to use a partial pack because you're doing small (1-2 gallon) batches or for some other reason?

 

[hlm123]

Thanks flars, that clears it up.

BF, that wasn't very clear sorry. I meant I would heat up the water in the microwave and funnel into a 300 mL flask. As I'm pouring it I remember the bowl hasn't been sterilized. Also, yes to 1-2 gal batches. I've been trying my first AG batches and some gluten-free stuff on a smaller scale.

 

[BigFloyd]

Thanks flars, that clears it up.

BF, that wasn't very clear sorry. I meant I would heat up the water in the microwave and funnel into a 300 mL flask. As I'm pouring it I remember the bowl hasn't been sterilized. Also, yes to 1-2 gal batches. I've been trying my first AG batches and some gluten-free stuff on a smaller scale.

Gotcha.

I try to keep it simple. I simply put about 3/4 cup of tap water in a Pyrex measuring cup and microwave it until it boils down to 1/2 cup. Then remove and cover with a piece of aluminum foil that's been sprayed with StarSan. I let that sit on the counter while I'm brewing. After I chill the wort, I check the Pyrex cup water for temp (with a sanitized thermometer) and rehydrate. Pitch straight from the cup into the fermenter after rehydration and attemperation are complete.