Weak ABV, OG & Depth of Flavor

[Russellmarc]

I'm a new all-grain brewer and I've brewed 3 batches so far. I use a 10-gallon Megapot with a false bottom for my MLT and another for my boil kettle. Beers taste great...but I'm getting consistently low OG, ABV and depth of flavor. I'm still learning my equipment, but these have been what I can see are my challenges to far:

1 - I'm using Northern Brewer all-grain kits. Are those kits made for 5.5 or 5 gallons going into the fermenter?? I called them but got conflicting information from different customers service people. I've been using 5.5.

2 - I measured 2 gallons under the false bottom, so I added that quantity of water to the 1.3 qts/lb of grain for my mash. My kits each contained 10.25 to 13.75 lbs of grain. Is my mash too thin? I batch sparge, with the sparge quantity being whatever I needed to bring me up to 6.5 gallons (assuming 1 gallon loss to boil). Generally my batch volume has been about 4.25 gallons.

3 - I'm having difficulty knowing when I'm at the right mash temp, and keeping that temperature consistent throughout the MLT. I have a Brewmometer and also a digital probe thermometer (both calibrated). I found the temp difference between the the two thermometers, testing in different spots in the mash, to be surprisingly high. Also once or twice after stirring, my temp went up 9 or 10 degrees. I guess heat builds up under the false bottom and gets released when I stir?? Maybe I just have to stir more frequently...and also raise the temp of my mash a little more gently. Make sense?

Any help would be appreciated. I've learned SO much from this forum. Thank you everyone for being so generous with your knowledge and experience!

 

[Yooper]

1. Pretty sure it's 5 gallons into the fermenter
2. A 1 gallon loss to the boil? You mean the boil off is 1 gallon? Or that you're leaving behind 1 gallon in the boil kettle? A water/grist ratio of 1.25-2 quarts per pound is ideal.
You're ending with 4.25 gallons in the fermenter? Or 5.5? Something doesn't add up. If you're finishing with 4.25 gallons after the boil, and then adding 1.25 gallons of water- well, that would make a huge difference in missing your desired OG! You don't want to do that.
3. A good thermometer is imperative. When you mash in, stir until the mash is the same temperature throughout. Stir, check the temp in a couple of places, and stir some more if it's different. The temperature should be the same throughout before you stop stirring. It's not possible for the temperature to go UP, so something is going on. Either the MLT is preheated too hot, or the water is too hot, or something. Generally, you preheat the MLT and use strike water about 10 degrees warmer than your desired mash temp to get into the ballpark for mash temp, depending on your system.

Can you type out a typical recipe, and the amount you put into the fermenter, and we can help you figure your efficiency and help spot what's going on?

 

[gbx]

3 - I'm having difficulty knowing when I'm at the right mash temp, and keeping that temperature consistent throughout the MLT. I have a Brewmometer and also a digital probe thermometer (both calibrated). I found the temp difference between the the two thermometers, testing in different spots in the mash, to be surprisingly high. Also once or twice after stirring, my temp went up 9 or 10 degrees. I guess heat builds up under the false bottom and gets released when I stir?? Maybe I just have to stir more frequently...and also raise the temp of my mash a little more gently. Make sense?

I had similar problem when i started doing all grain because I was aiming for a specific mash specific mash temp that was recommended in recipes. If you are direct heating but not recirculating there are going to be hot spots. Try aiming for a very low temp like 60C and see how it turns out - the worst that will happen is it will be very dry.

In regards to depth of flavour, that could be a fermentation problem. What yeast are you using?

 

[Russellmarc]

-1 gallon evaporation loss to the boil.

-I'm ending up with 5.5 gallons going into the fermenter. After my first runnings of about 2.25 gallons, I sparge with about 4.25 gallons, making the volume that I'm boiling 6.5. I lose 1 gallon to evaporation, and get 5.5 gallons into the fermenter.

-I didn't preheat the Megapot, but I did use strike water that was about 10 hotter than mash temp. I'll preheat the kettle next time.

-Recent stout recipe:
13.75 grain, almost 18 quarts of water, (1.3 quarts water/lb), plus 2 additional gallons of water (compensation for water under false bottom) mashed at 152 (overshot at first, had difficulty keeping it steady), collected 2.5 of first running, with 4 additional gallons of 170 degree water, OG 1.060 (was shooting for 1.068), ended up with a little more than 5.5 gallons going into the fermenter. FG 1.033 (my fermentation temp was 62...a little on the low side.) ABV 3.8. Beer is great, but lacks depth of flavor.

 

[Russellmarc]

For yeast...I've been making 1200 ml yeast starters, using Wyeast liquid yeast. Fermentation starts quickly, and is very visible for about 5 days...then simmers down. I'm fermenting for 4 weeks and then going to bottles. Fermentation temp has been a bit low about 62 degrees. That could, at least in part, explain why ABV is low.