calculating gravity points prior to sparge

skelley

I know how to calculate gravity points needed at preboil but I am not sure how to calculate the gravity you need be at prior to beginning run off into boil kettle given a known sparge volume. Does anyone know a method to determine this?

MtnBrewer · Joined: 19 Feb 2013 Posts: 29 Location: Colorado Springs

The gravity of your first runnings will depend on your mash stiffness. The stiffer the mash the higher the first runnings gravity. Use the chart below to find the gravity you should be at for the mash stiffness you're using. When you've reached this value, conversion efficiency will be at 100%.

Kevin59 · Posted: Tue Mar 26, 2013 3:26 pm Post subject:

So given that we're recirculating during the mash, should we just consider "first runnings" to be the entire volume of wort in the MLT prior to sparging?

MtnBrewer · Joined: 19 Feb 2013 Posts: 29 Location: Colorado Springs

skelley · Posted: Wed Mar 27, 2013 5:43 pm Post subject:

This chart is the key to determining your conversion efficiency. I do not know about others but I have not hit 100% yet. My understanding is that anything 95-100% is considered good. I have noticed that my conversion efficiency continues to go up if I mash more than an hour. Not sure what that says to all the talk I listen to suggesting that conversion is complete after an hour. That may be for regular and low gravity beers but not my experience with high gravity beer (>1.075)

MtnBrewer · Joined: 19 Feb 2013 Posts: 29 Location: Colorado Springs

huaco · Joined: 05 Apr 2012 Posts: 1506 Location: Burleson Texas

Ok... So I'm a bit lost on this chart. This is simply showing CONVERSION right??? It is not mash efficiency right?

MtnBrewer · Joined: 19 Feb 2013 Posts: 29 Location: Colorado Springs

It's conversion efficiency, not lauter efficiency. Conversion eff * lauter eff = brewhouse efficiency (which I think is what you're calling mash efficiency?).

huaco · Joined: 05 Apr 2012 Posts: 1506 Location: Burleson Texas

So if I read this right, if I am mashing with 1.24 qt/lb once the SG reaches 1.096, that's it... Done. No need to mash longer than that?

MtnBrewer · Joined: 19 Feb 2013 Posts: 29 Location: Colorado Springs

Holter · Joined: 07 Oct 2011 Posts: 221 Location: Los Angeles, Ca

Thats an interesting chart, ive never seen that before. I am trying to wrap my head around it - basically what that chart is saying is that with any quantity of grains you should achieve the same exact sugar count each time regardless of if you use 10lbs or 50lbs in your mash because the constant variable is your water to grist ratio. I suppose that makes sense although i would rely on people smarter than me to take it as a certainty, but if it was it would be a valuable troubleshooting tool. If you check your presparge wort gravity consistently and see the same results over and over then you know that your mash routine is dialed in. At that point your efficiency would be solely determined by your sparging techniques and your fermentability would still be controlled by your mash temp, grain selection and duration.

I think the part that confuses me is what if i put 5 lbs of crystal 40L into my mash and nothing else? There is virtually no diastatic power to crystal malts meaning you may not get sugars out of it? I know crystal malts do not contribute much in the way of fermentable sugars, but they do contribute sugars nonetheless. Im not suggesting the chart is flawed, but im trying to point out that if a brewer chose malts that didnt have enough diastatic power there would be less conversion and this chart doesnt take that into effect right? Does that even matter though? Where did you find that chart? Id love to see more info about it because if it works that would be an awesome way to improve repeatability that i never thought of.

Holter · Joined: 07 Oct 2011 Posts: 221 Location: Los Angeles, Ca

Kevin59 · Posted: Sun Mar 31, 2013 1:13 am Post subject:

Here's a link to braukaiser's full page...

http://braukaiser.com/wiki/index.php?title=Troubleshooting_Brewhouse_Efficiency

MtnBrewer · Joined: 19 Feb 2013 Posts: 29 Location: Colorado Springs

CapnBry · Joined: 20 Oct 2012 Posts: 53 Location: Tampa, FL

This topic is very interesting. I usually just mash until the iodine test looks good then move on and my (brewhouse) efficiency tends to be mid-70%s. I'm interested to start tracking this.

MtnBrewer · Joined: 19 Feb 2013 Posts: 29 Location: Colorado Springs

CapnBry · Joined: 20 Oct 2012 Posts: 53 Location: Tampa, FL

I think you're right about that. Basically use total volume of water (including deadspace and coil) divided by grain weight, as the sugars should be evenly distributed throughout the liquid regardless of if it is under the false bottom or in the tubing.

I think I'll change my procedure from using 1.25qt/lb + 0.5g tubing + 0.19 deadspace to just using 1.5qt/lb flat (for most ales anyway). With my additions I was ending up at 1.40qt/lb for a 9 gallon batch and 1.49qt/lb for a 5 gallon batch anyway. Every time I learn something I immediately want to brew a batch to try it out. I need to step up my drinking to empty a keg.

MtnBrewer · Joined: 19 Feb 2013 Posts: 29 Location: Colorado Springs

skelley · Posted: Mon Apr 08, 2013 1:24 pm Post subject:

I just brewed an APA with 30lbs of grain, milled at .040 and mashed with 11.25gal of water for a full 1.5 hours. I was able to run the pump wide open and temperatures tracked perfectly mashing at 149. My pH was 5.45. The odd thing is I could only get my first runnings to 1.069. I can not figure this out. Is it possible that I was getting channeling? Should I slow down the pump to give a longer contact time with mash? I ended up ok by simply running almost a 1hour 45 min sparge and grabbing an extra gallon to boil off. Any ideas?

**kal** · Posted: Mon Apr 08, 2013 1:30 pm Post subject: