OG lower than in the recipe

[zwbsch]

Hello all,

I have now started my 4th attempt to brew beer. In the first two my OG was always 1/3 lower than you should be according to the recipe. Mostly I have then compensated by less water.

Now I have planned on 6 gallons and used significantly more malt.
14.8 lb (6.75 kg) German Pilsner Malt
1.6 lb (750 g) Malted White Wheat 0.75
2 lb (900 g) Golden Candi Syrup

Original recipe
5 gallon (19 liter) batch
10 lb (4.5 kg) German Pilsner Malt
1 lb (450 g) Malted White Wheat
1 lb (450 g) Golden Candi Syrup (15 min.)

Target was an OG of 1.059, I was at 1.042 with 4 gallons. Way too low in my opinion.

About my mash process, I used a boil-in with BIAB (with a boiling machine) and tried to keep the temperature as close as possible.
Every 15 minutes I stirred the malt, total was 1 hour, 15 minutes in the pot.
I started at 143F (62 °C) (first 15 minutes). The last half hour was at 158-163F (70-73°C).
Malt out, and boiled for 1 hour.

I let the bag of malt drip out for several hours, then added the remaining liquid.

Still only an OG of 1.042, can anyone tell me what I can do differently with my equipment? Thank you.

 

[Erik the Anglophile]

Have you measured your boil off rate? It might be that it's lower than you think and you start with too much wort. And after you have done that, you might not loose as much water to the grains as thought.
Try boiling a wort equivalent amount of water in your kettle for an hour, measure carefully before and after, and calculate your new amount of water from that. And then use a little less than that, it's always easier to top up a little before boil than reducing the wort.

 

[madscientist451]

With only 4 gallons of wort, your gravity should have been higher than expected, not lower. Increasing your malt by 50% and your candi-syrup by 100% is not the answer, your doing something wrong with your process.
What is a "boil in" when mashing? Are you using boiling water at the start of the mash?
What was the wort temperature when you took the gravity reading?
How are you achieving the step mash? Why 158-163?
What method are you using to maintain your mash temp.
When I started BIAB, I used bottom heat to raise mash temp during the mash, had temperature swings, and all kinds of problems.
These days I use a strike water calculator, usually always hit my desired temperature, then wrap up the kettle in an old sweatshirt and let it sit an hour or more. No stirring, no checking the temp, just leave it alone. Meanwhile, I heat water for a dunk sparge in a smaller pot and when the mash is done, I stir it, pull the bag, let it drain a little and then place it in the dunk sparge pot. If you don't have another pot you can use a bucket and cold water. I stir the dunk sparge a little then pull the bag and start the boil. If you want to do a step mash with BIAB the best method is to heat a measured amount of water in a smaller pot to boiling and stir it in. The amount of water used is determined by using an online step mash calculator. Using this method provides very high efficiency and again I usually hit all my desired numbers.

 

[bruce_the_loon]

Two things come to mind immediately.

First, what does your crushed grain look like? If it is too coarse, you'll get bad extraction of the starches and therefore a lower OG. There are a number of threads on grain crush that go into detail.

Secondly, I think your temperature profiles are adding to the problem, if not the entire cause. The 143F start is in the middle of the B-Amylase range, but most systems recommend around 148F for a light body and to mash for at least 90 minutes at 148F. You're then running for half a hour at a temperature you haven't mentioned, and then hopping to the far end of the window for a-Amalyase for another half an hour. I think you are not mashing for long enough and possibly causing temperature denaturing of the amylase enzymes.

For a BIAB mash with your specifications, BeerSmith is predicting a 1.055 OG on my equipment with a 90 minute mash at 148F for a light body, 75 minutes at 152F for a medium body and 60 minutes at 156F for a full body. It starts with 35L of water in the mash, predicts 32L after the bag is removed and then a boil off down to 27L and 23L going into the fermenter.

In summary, check your grain crush. If it is too coarse, e.g. grain kernels broken in half only and some unbroken, then you'll have efficiency problems for sure. Check out the crush threads. Then do a simple single infusion mash instead of trying to shift temperatures around, leave that for when you have the rest of the system dialed in. As Erik suggested, test your boil-off rate. My numbers above are based on a boil-off rate of 3.2L per hour.

 

[zwbsch]

I use the Stagecaptain GWK-27A (7gallon) with bottom heat, put the malt in, fill it to the top with water, and make sure that I always stir around a bit so that the temperature is even. With the Stagecaptain, the switching points and where it heats up to are a little difficult to gauge though.

After that I usually just have 3 gallon mash and fill that up with water, bring it to a boil and keep going.

I measured the OG at room temperature. Is probably better if I determine the amount of water that will fit in the kettle with the malt, then bring it up to temperature and add the malt. And then keep that with shown graphic.

How my crushed grain looks like I can not say right now.
For me it is certainly not 35 liters of water in the mash. rather 12L. For this I would rather need a 50L boiling machine than 27L. The 27L is with 7kg grain already at least half full.

I must test the temperature again better before I start the next time. My container is probably just too small. Thanks for the good help.

 

[RM-MN]

I use the Stagecaptain GWK-27A (7gallon) with bottom heat, put the malt in, fill it to the top with water, and make sure that I always stir around a bit so that the temperature is even. With the Stagecaptain, the switching points and where it heats up to are a little difficult to gauge though.

Your order of operations is wrong. Heating the water and grain together requires constant and vigorous stirring until the mash temperature is achieved. You probably have denatured a majority of the enzymes that do the conversion before you reach mash temp because the bottom gets too hot before the entire mash reaches temp. Put the water in first and heat that by itself until it reaches "strike temp" which will be a few degrees above mash temp, then stir in the grains.

 

[DannyBoy270]

Your order of operations is wrong. Heating the water and grain together requires constant and vigorous stirring until the mash temperature is achieved. You probably have denatured a majority of the enzymes that do the conversion before you reach mash temp because the bottom gets too hot before the entire mash reaches temp. Put the water in first and heat that by itself until it reaches "strike temp" which will be a few degrees above mash temp, then stir in the grains.

+1 this

I'd also drop the step mash for now and just suggest just a single infusion in the range of 148-152F for about an hour.

 

[bailey mountain brewer]

I agree with both of the last 2 posts and also earlier one about crush. If your not milling your own grain I'm not sure you'll get to take full advantage of your biab system as that is being able to have a finer crush. If your getting your grains from a lhbs tell them you are using biab and want a finer crush or atleast ask them to mill the grain twice. Depending on the lhbs they may or may not do that for you. Then as mentioned above calculate your strike water volume and temp, heat that first then stir in your grain. I use beer Smith to calculate this and usually it gets within 1 degree of target. Mash at 148 to 152 for an hour, not sure how your equipment is set up for mash out or sparge as I have not yet looked up that model that you posted.

 

[IslandLizard]

All of the above, crush, heating mash, etc. ^

After that I usually just have 3 gallon mash and fill that up with water, bring it to a boil and keep going.

Adding top up water is very counterproductive. It doesn't do anything for your mash or mash efficiency.
That bag with wet grains you pull holds onto quite a bit of high gravity wort, that's being wasted. Either mash with all the water, or better, save some for a (dunk) sparge. You should end up with your pre-boil volume that way.

Does your BIAB kettle recirculate during the mash? How much wort is kept underneath the bag?

 

[zwbsch]

I like the beersmith software. Otherwise, I have now ordered a grainfather s40 in a good offer. Were still a few in stock, so I bought right away. Then it is just a hobby that costs more money than it brings in.
Previously there was no circulation with the BIAB method.
I think the biggest problem is that I processed too much grain with too little water. Plus the temperature fluctuation. In a product description I saw that per kg, 4L of water should be used in automatic boilers.

 

[GoodTruble]

Are/were you mashing that grain bill in 3 gallons of water? (Sorry if I read that incorrectly). If so, too little water may be the problem (-which the s40 will solve - that looks like a great brewing machine btw).

If I misread, then my next guess is crush or possibly water. If you are using only reverse osmosis or distilled water, it may lack the minerals for higher extraction. Also small chance it is the grains themselves that weren't great, but that seems less likely.

Also, the ultimate OG shortcut is just keep a few pounds of light/extralight DME onhand. If you come up short, just mix some in.

 

[zwbsch]

I also think the S40 will be great. I use normal tap water, but we should have high minerals in it. When i mashed I had only 3 gallons left.
Before the mash I dont know how much water I put in. I put in the grain 7,5kg (16,5lb) and filled up the 27l (7gal) pot with water.
I measured the temperature at the top (after stiring) every 15 minuts and it was ok.

 

[PCABrewing]

All of the above, crush, heating mash, etc. ^


Adding top up water is very counterproductive. It doesn't do anything for your mash or mash efficiency.
That bag with wet grains you pull holds onto quite a bit of high gravity wort, that's being wasted. Either mash with all the water, or better, save some for a (dunk) sparge. You should end up with your pre-boil volume that way.

Does your BIAB kettle recirculate during the mash? How much wort is kept underneath the bag?

I would propose the additional sparge too. You could pour the last bit through the top of the bag.
This in addition to the other proposed adjustments.

 

[hotbeer]

I let the bag of malt drip out for several hours, then added the remaining liquid.

Remaining liquid = make up water to get to the recipe volume for the boil?

Did you add the water to the bag of grain or just straight into the boil kettle or fermenter?

If you didn't run it through the grain then you did leave a lot of sugar in it depending on the quantity of water you mashed with.

I currently move my bag of grain to another vessel of mash temp water and rinse the bag in it. Sometimes I move it to for a second rinse. However I only do very small one gallon or so batches. So maybe the logistics and handling will be different.

 

[PCABrewing]

I would propose the additional sparge too. You could pour the last bit through the top of the bag.
This in addition to the other proposed adjustments.

Have you inspected the spent grain?
There should be mostly barley hulls and very little remaining endosperm. Unscientific I know but you can learn something from how it looks mash to mash.

 

[zwbsch]

The cereal should be okay, if not i'll order from somewhere else next time. Sparge is important, they also do it in the product presentation of s40. Saturday i ordered the s40 and today the same offer is sold out... lucky me