Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.


Messages - mabrungard

Pages: 1 ... 56 57 [58] 59 60 ... 93
856
Nope, not even a Gose is crafted with that high a sodium level.  In talking with some successful pro Gose brewers, they take the sodium level as high as 300 ppm.  But that is through a post-fermentation dosing of salt.  You probably would not want to take sodium above a couple hundred ppm for a good ferment.  The osmotic stress would adversely affect the yeast unless most of the other ions are low.

857
Yeast and Fermentation / Re: Aerate Starter?
« on: April 07, 2012, 10:44:35 AM »
The problem with a shot of Oxygen in a starter is that unlike beer, we are looking to KEEP the starter aerobic throughout the yeast's growth stage to develop a high level of sterols in the yeast.  The stoichiometric mass of oxygen to completely oxidize a sugar is about 94% of the sugar's mass.  Fortunately yeast can't fully oxidize sugars, so the oxygen demand is less than the stoichiometric value.  So that might mean to oxidize 1 gram of sugar, we might need to supply maybe 0.7 grams of oxygen.  I think we all know that oxygen is not very dense and that it takes a large volume of gaseous oxygen to provide that 0.7 grams. 

So moving a bunch of air through the headspace over a starter wort is a better way to keep a consistent oxygen supply to the wort through the yeast growth phase.  Since air is only about 21% oxygen, that means that roughly 5 times the volume of air will be needed to provide the volume of oxygen needed.  But air is cheap.  And since yeast cannot instantly utilize oxygen, a long-term delivery of a low dose better matches the yeast utilization rate. 

This does not change the fact that oxygenation is best for wort when making beer.  But for a starter and its differing oxygen requirement, continuous aeration with air is more suitable.

I agree with that comment that Nate made: if the yeast are healthy and pitched at high rate, there may not be a need for wort oxygenation when making beer.  For most of us that probably underpitch, a shot of O2 is good insurance!

858
All Grain Brewing / Re: Dry Lagers
« on: April 06, 2012, 11:38:15 AM »
There are several ways to create the perception of dryness.  Creating a highly attenuable wort is one way.  Another is to have elevated sulfate content that creates a perception of dryness.  Another is to oversparge or improperly sparge and infuse a slight amount of tannin in the wort. 

All of these causes can can be created by the water used for brewing.  Of course, you should also recognize that water may also not be the cause.  It is wise to know what your water is and understand if there are things that can be done with the water to avoid creating this result again.

859
Yeast and Fermentation / Re: Aerate Starter?
« on: April 06, 2012, 09:46:48 AM »
But now I wonder, would it not be better even than a stir plate to get an aquarium pump and a sterile filter and just continously bubble air through the starter?

It sure wouldn't hurt, but be careful with the rate and way the air is bubbled.  I struggled with this for years.  Even though I use a 6L Erhlenmyer, I was occassionally creating 'bubble-overs' if I bubbled air through the wort.  Its much worse if an air stone is used since the bubbles are much finer and frothy.  I use the same low gravity wort made from DME for all my starters.  I found that the tendency to bubble-over is a function of the yeast strain.  Hefeweizen yeasts were particularly bad for me. 

That is how I came to my current recommendation to just flood the headspace above the wort with filtered air and let the stir bar do the rest of the oxygen transfer.  No bubbling this way.  If a stirrer is not used, then I suppose that bubbling the filtered air through the wort is the way to go.  Just be sure to use a vessel that is way bigger than the amount of wort so that bubble-overs don't make it out of the vessel.  By the way, those bubbles carry a huge amount of yeast, so loosing that foam is not good for your final yeast count. 

860
Yeast and Fermentation / Re: Aerate Starter?
« on: April 06, 2012, 05:35:22 AM »
Unless you are pumping filtered air into the starter vessel while its on the stir plate, you aren't getting a good aeration of the wort during its growth phase.  Stirring is very good for improving the transfer of gases from the atmosphere above the wort, into the wort.  But if the atmosphere above the wort is depleted of oxygen, all the stirring in the world won't make any difference.  During active fermentation, that atmosphere will have little oxygen and a high percentage of CO2.  If an Erhlenmyer flask is used as the starter vessel, the avenue for gas transfer is restricted.  To keep contaminants out, we typically have some sort of barrier (foil, foam) over the flask mouth.  That is an impediment to gas transfer and diffusion.  An active flow of filtered air into the flask alleviates this deficiency.  There is no need to bubble the air through the wort, just exchange the atmosphere.

Enjoy!

861
Equipment and Software / Re: How to use a pH meter
« on: April 04, 2012, 12:03:31 PM »
Can you store them with the probe immersed in distilled water?

No.  The probe is filled with a ion-saturated (typically potassium) solution or gel.  Its important to keep that solution saturated with that ion.  The glass probe is actually permeable.  Immersing the probe in a solution with very low ionic strength creates an osmotic pressure that draws those ions out of the probe and into the exterior solution.  You end up depleting the ion solution inside the probe.  pH probe storage solutions are typically high in the particular ion and when the probe is immersed in that solution, then there is not the osmotic stress drawing ions out of the probe.  The probe solution stays saturated.

862
Equipment and Software / Re: How to use a pH meter
« on: April 04, 2012, 04:57:46 AM »
I don't ever wipe the bulb on my pH probe.  The whole probe gets a distilled or RO rinse and then I blow out the droplets by mouth.  I suppose it would be even better to blow it off with compressed air, but its not like I'm spitting on it.  The blowing gets the droplets out from around the protected bulb area.  Then I can use a regular paper towel on the exterior of the probe housing to absorb those droplets.  It usually takes a couple of blows and wipes to get the bulb and probe dry.

863
General Homebrew Discussion / Re: Okay Princess Bride fans...
« on: April 03, 2012, 02:16:23 PM »
To Blathe (true love)

864
Ingredients / Re: Rahr 2 Row Attenuation
« on: April 02, 2012, 11:23:44 AM »
I use the 2-row Pale

865
Ingredients / Re: Northern Brewer hops question
« on: March 30, 2012, 09:52:52 AM »
PS: I do late hop and dry hop with NB.  The flavor and aroma come out then.

866
Ingredients / Re: Northern Brewer hops question
« on: March 30, 2012, 05:50:28 AM »
I've been a long time user of NB hops in my American Brown Ale.  I've never characterized their flavor or aroma as minty.  I find them to be more woody.  They are a good compliment to Hallertau and Cascade hopping.

867
Yeast and Fermentation / Re: Starter
« on: March 30, 2012, 05:45:02 AM »
Hefeweizen is one of the few styles where you might not want to make a big starter.  The increased yeast growth required from modest underpitching can be helpful in creating a fruitier ester profile in the flavor. 

I make big starters for my typical ales and that includes my Hefe's.  I could enhance the fruitiness if I cut that starter size back a bit.  I still suggest that a starter is always a good idea for 'proofing' your yeast and enhancing their glycogen reserves. 

868
Equipment and Software / Re: How to use a pH meter
« on: March 29, 2012, 12:45:10 PM »

I got to Milwaukee tech support again today and they agree that my meter seems flaky. They are going to replace it free of charge so we'll see if that helps.

I've had the Hanna meters for years and they are alright.  I recently moved to Milwaukee meters and am pleased.  I use the MW-101 and it works very well.  Hopefully this replacement will solve your problems.

869
Ingredients / Re: White Table Sugar
« on: March 26, 2012, 10:58:36 AM »
I am in general agreement with respect to white sugar or corn sugar...there is little difference.  When you get into the less refined sugars, then you are talking about flavor nuances that can be desirable. 

Another aspect that came up at my club's meeting on Saturday was the issue of "Inverting" the sugar with heat and an acid.  The thought was that you are saving the yeast from having to enzymatically invert the sugar prior to consumption.  It seems easy enough, but is it needed or necessary in brewing and fermenting?

870
Equipment and Software / Re: Tubing storage and sanitization
« on: March 25, 2012, 10:27:09 AM »
you mention a liquid with nutrients present is needed to grow nasties. I'm based in Indy also (we've met briefly at a couple of FBI functions)  - in your expert water opinion do you think our city water has enough nutrients for this to occur?

Well, aquatic life requires 3 building blocks to grow: carbon, nitrogen, and phosphorus.  There is a concept termed the Redfield Ratio that says that this life needs 106 parts carbon, 16 parts nitrogen, and 1 part phosphorus to grow.  As seen from that ratio, only a minute amount of phosphorus is needed and most waters do have phosphorus at very low levels.  Many waters also contain 'active' nitrogen compounds like nitrate.  Nitrate can be present at low to modest levels in water supplies, especially anywhere that agriculture is practiced.  As indicated above, the biggest component for life is carbon.  For most water supplies, carbon compounds are not present at significant levels.  Carbon content would have to be significant in the water.  Therefore as long as you have rinsed the tubing to adequately remove any carbon sources (sugary wort is a huge carbon source), its unlikely that the remaining rinse water would have the carbon needed to promote biologic growth.  Carbon is the limiting component.

Pages: 1 ... 56 57 [58] 59 60 ... 93