Should I compensate for boil off? Also, how to get steady mash temps?

I'm extract brewing and my kit instructions have said to start the boil with 2.5 gallons, chill and top up with another 2.5 in the fermenter. With the goal of a 5 gallon batch, should I most likely be adding more than 2.5 gallons to compensate for boil off? Or does the kit assume this and the batch size is really under 5 gallons?

As far as steeping grains or partial mashing, can someone give me advice on maintaining a steady temperature on my electric stove? I've been just steeping inside my boil pot but I'm constantly overshooting my target temp and then having to turn the burner off completely and move the pot to a cold burner. Then it'll start to drop so I move it back only to encounter the same problem.

Thank you!

Boil as much as you can manage (too much makes boiling more difficult or nearly impossible on an underpowered electric stove).

For your steady temp issue, all I can suggest is to stay on top of it and monitor. As it goes too high, turn the burner down slightly as you remove the pot to a cold burner, then stir until the temp gets where it needs to be. Then put it back on the burner. Repeat. That's my best advice not knowing more about your setup.

My best luck on pm has been to use a calculator to determine strike temp, add grains, and put it in an oven set to 170 (min for my oven) then turned off. The hot air insulates pretty well.

This assumes your bk fits in your oven... Mine is really close.

freisste said:

My best luck on pm has been to use a calculator to determine strike temp, add grains, and put it in an oven set to 170 (min for my oven) then turned off. The hot air insulates pretty well.

This assumes your bk fits in your oven... Mine is really close.

Click to expand...

I've also held decent temperatures this way (assuming your oven will hold your pot). Preheat to 170F, turn off, put your mash in after reaching desired mash temperature.

I've read about the oven trick. I saw two problems. The first is my brewpot will not fit and second, I'd like to mash lower than 170.
Another strategy I might try next time is to start my mash water volume a bit lower, and when my temps start to creep up slowly add fresh ice cold water to bring it down a bit.

For my boil off issue. I'm thinking the best way to approach this is to just mark my carboy for 5 gallons and top up to the mark.

When I used a spackleware canning kettle for partial mashes, I built a box out of plywood, then lined it with insulation. I got the mash to temperature on the stove, then stuck the kettle in the box. It stayed right at temperature.

I still have the box--and now I use it for cheese making (same temperature control issue).

If you aren't into making a box, you might try wrapping your pot in blankets, or dropping it in a cooler (if it will fit) stuffed with towels or blankets.

brevity said:

I've read about the oven trick. I saw two problems. The first is my brewpot will not fit and second, I'd like to mash lower than 170.
Another strategy I might try next time is to start my mash water volume a bit lower, and when my temps start to creep up slowly add fresh ice cold water to bring it down a bit.

Click to expand...

You don't actually mash at 170, just preheat the oven to 170 and turn it off. Then, when you add your pot you let out a huge wallop of heat which brings down the temperature within a couple minutes. Additionally, you're adding a large, cooler mass to the oven with a much lower temperature which brings down the temperature even more. Third, the oven is off so it's continuously losing heat the whole mash time. Lastly, you're basically surrounding your closed mash container with air that is slightly higher in temperature for about an hour - just to keep your mash temperature steady. The net effect is that the temperature inside your mash container remains much more constant than trying to keep temperatures on the stovetop.

Imagine putting a room temperature beer (~70F) into your refrigerator (~38F) and pulling it out an hour later to drink - still way too warm, right? Now imagine it's a giant 2 gallon beer in a bottle - how much is the internal beer temperature going to change in 1 hour (a degree, maybe 2 or 3)? And this example is using a 32+ degree difference which would equate to quicker change in temperature for the beer. Putting a 154F two gallon full pot in your 165F oven (an 11F difference) to sit for only one hour, AND the oven is losing temperature the whole time, is going to equate to pretty stable temperatures inside the pot.

HOWEVER, if you can't get your pot in the oven then you can't get your pot in the oven - no way around that.

stpug said:

You don't actually mash at 170, just preheat the oven to 170 and turn it off. Then, when you add your pot you let out a huge wallop of heat which brings down the temperature within a couple minutes. Additionally, you're adding a large, cooler mass to the oven with a much lower temperature which brings down the temperature even more. Third, the oven is off so it's continuously losing heat the whole mash time. Lastly, you're basically surrounding your closed mash container with air that is slightly higher in temperature for about an hour - just to keep your mash temperature steady. The net effect is that the temperature inside your mash container remains much more constant than trying to keep temperatures on the stovetop.

Imagine putting a room temperature beer (~70F) into your refrigerator (~38F) and pulling it out an hour later to drink - still way too warm, right? Now imagine it's a giant 2 gallon beer in a bottle - how much is the internal beer temperature going to change in 1 hour (a degree, maybe 2 or 3)? And this example is using a 32+ degree difference which would equate to quicker change in temperature for the beer. Putting a 154F two gallon full pot in your 165F oven (an 11F difference) to sit for only one hour, AND the oven is losing temperature the whole time, is going to equate to pretty stable temperatures inside the pot.

Click to expand...

This makes total sense. The way I've read people explain (in few words) I thought people were leaving their ovens turned on. Not to mention, I didn't take water capacity and temp change rate into consideration.

As far as my pot not fitting, could I just use a different smaller pot for my mashing and then pour it into my brew pot after?
Would there any issues using a standard steel cooking pan?

I used to use a smaller ~2 gallon stock pot which, according to rackers, can hold about 5-7 pounds of grain depending on water:grain ratio, however it was stainless. After the mash I would remove my bag of grains, sparge the grains, and move everything into my main brewpot. I would guess that most cookware, specifically stock pots, are going to be stainless or aluminum since they'd be seeing water usage all the time and nobody wants a rusty pot (either of these metals would be good; even enamel pots are fine, barring any chipping/rusting).

stpug said:

You don't actually mash at 170, just preheat the oven to 170 and turn it off. Then, when you add your pot you let out a huge wallop of heat which brings down the temperature within a couple minutes. Additionally, you're adding a large, cooler mass to the oven with a much lower temperature which brings down the temperature even more. Third, the oven is off so it's continuously losing heat the whole mash time. Lastly, you're basically surrounding your closed mash container with air that is slightly higher in temperature for about an hour - just to keep your mash temperature steady. The net effect is that the temperature inside your mash container remains much more constant than trying to keep temperatures on the stovetop.

Imagine putting a room temperature beer (~70F) into your refrigerator (~38F) and pulling it out an hour later to drink - still way too warm, right? Now imagine it's a giant 2 gallon beer in a bottle - how much is the internal beer temperature going to change in 1 hour (a degree, maybe 2 or 3)? And this example is using a 32+ degree difference which would equate to quicker change in temperature for the beer. Putting a 154F two gallon full pot in your 165F oven (an 11F difference) to sit for only one hour, AND the oven is losing temperature the whole time, is going to equate to pretty stable temperatures inside the pot.

HOWEVER, if you can't get your pot in the oven then you can't get your pot in the oven - no way around that.

Click to expand...

And for steeping a constant temp just isn't important so the oven is really nice for that since it's set and forget...no fussing with burners. You can find a smaller pot of steeping since it's usually only a couple pounds of grain, and just use a ratio 1.5 quarts per pound for the water.

helibrewer said:

You can find a smaller pot of steeping since it's usually only a couple pounds of grain, and just use a ratio 1.5 quarts per pound for the water.

Click to expand...

Does water ratio matter when there are no base malts involved? For example my next kit has me add the 1lb of caramel/carapils to the full boil volume. Whereas, my last kit was very specific about the water ratio when the steeping (I guess partial mashing at this point) involved 2-row malt.

brevity said:

Does water ratio matter when there are no base malts involved? For example my next kit has me add the 1lb of caramel/carapils to the full boil volume. Whereas, my last kit was very specific about the water ratio when the steeping (I guess partial mashing at this point) involved 2-row malt.

Click to expand...

Just carapils means that you are steeping, not mashing. In this case, the exact amount of water and temperature are not nearly as important as with mashing. However, many people will suggest that you practice mashing with your steeping grains, simply because it has most of the same actions and you an get your process down.

Mashing involves enzymes. Different grains have different amounts of these enzymes. Some have lots, some have enough to convert themselves, and some have very little. The grains with little amounts of enzymes need another malt (with extra enzymes to share) in the mash so they can convert. That is why 2-row is used so often in mashing and in general in beers throughout history. It has enough enzymes to convert itself and an equal amount of another grain.

As far as temps, when you mash you need to be between about 145 and 160f. At the bottom of that range, beta amalase is produced. At the top of the range, alpha amalase is produced. Both break starches into simpler sugars. However, alpha tends to break sugars up randomly, resulting in fermentable and infermentable chains. Beta is much more uniform, resulting in mostly fermentable sugars. That's why temps are important. A couple degrees makes a big difference in fermentable sugars and thus ABV, body, and residual sweetness.

Again, crystal grains have had their sugars extracted prior to you receiving them, so you are essentially just rinsing sugar out of them. So like I said, do your best to "mash" just to get the process down, but certainly don't sweat it if your temps aren't exactly right. It won't hurt a bit in steeping grains.