Low Gravity..Partial Mash...advice?

[digphish]

So this is my second parital mash attempt. The first was a hefe that went well. I over shot my gravity and came out at 1.062. So I tried "hophead's" Flat Ass Tired--fat tire clone. However, I needed to convert his recipe to partial mash. Here is what he called for:

6lb 2-row
2lb amber malt
1lb munich
.5lb biscuit
.25lb 10L
.25 40L
.25 special roast

I converted it to:
4.2lbs extra light dme (figured 6-lb 2 row + 1lb amber = 7lbs grain x .6= 4.2lb dme)
1lb Amber
1lb munich
.5lb biscuit
.25lb 10L
.25 40L
.25 special roast

So following death brewer's parital mash instructions, I used 1.25qt/lb which came to about 1 Gallon. I mashed at 152 for 60 minutes, then sparged in 2 gallons of 170 degree water for 10 minutes. drained and combined worts and brought to boil. Brewed as usual with hop additions at 60 min, 30 min, 15 min, 5 min. At 15 minutes I also added irish moss and the DME. Cooled wort to 72 and put in my glass carboy (which is the first time using glass). Added about 2.5 Gallons of cool water to bring the total volume to 5.25 G. I then shook it as well as I could and pulled a sample that showed 1.030. Thinking that this was way low, I shook the carboy again, and pulled and got 1.030. Did I do something wrong? Was it the recipe? Or do you think that most of the wort sunk to the bottom of the carboy, and the beer is probably around 1.050? If the latter is the case, why can't I get a good reading any more? I used to have no problems getting accurate readings, but it seems like lately I have been having issues with my gravity.

BTW, it is bubbling along nicely 8 hours later!

Thanks for any and all feedback.

 

[Walker]

It is very possible that your mash did not have enough enzymes to convert all of the starches to sugar.

Munich has enough diastatic power to convert itself, but no leftover power to really convert anything else. Crystal needs no conversion. I'm pretty sure that none of the other grains have any enzymes at all, so they won't be able to convert to sugar without some help from somewhere. It's always a good idea to include some basic 2-row in your partial mash for this reason. 2-row can convert itself and has enough power to convert some other grains that need assistance.

However.... I do think there is something wrong with your gravity reading in addition to the above potential issue.

The 4.2lbs of DME in 5 gallons of water all by itself should have given you close to 1.040

You mentioned that you have been having gravity problems recently. Perhaps your hydrometer is reading incorrectly? Have you put it into plain water to see what it reads?

 

[digphish]

just checked the hydrometer and it is 1.00 at 60 degrees. I am thinking it has to be that I pulled more water than wort on both samples. I do recall that even after i shook it and took the reading, there was a lot more sediment and stuff in the bottom half of the carboy, and the top looked a bit lighter. I don't know how to get an accurate reading without shaking it for 10 minutes. It is bubbling away right now, and looks and smells awesome. I am thinking it will be fine... I hope. I will be moving to all grain soon enough, so I won't be dealing with top off water issues any more.

 

[Walker]

I will be moving to all grain soon enough, so I won't be dealing with top off water issues any more.

Well.... yes and no. You might find on warm days that you boiled off more than you intended, so you could end up having to add top-off water even for an AG batch.

 

[david_42]

Consider taking a gravity sample before adding the extract. That will give you a more accurate indication of how well the mash went.

 

[digphish]

That is also a good idea. I'm guessing i will really need to compensate for temperature right? What would be a good gravity reading for a mash?

 

[ChshreCat]

You can chill a hydrometer sample down really quick in the sink.