2 things - (rehydrating yeast and late extract addition)

Rehydrating the yeast.. why? I read the package on my yeast and it said just to sprinkle into the wort. What is the advantage of rehydrating it?

Saving some malt for later in the boil. My LHBS said add all the malt at the 60min mark, I've been told to save some if not half to later in the boil... why?

1. To wake your yeast up and reduce lag time (amount of time before fermentation starts), helps reduce ester production.

2. To help keep the color lighter, and increase hop utilization. This is only necessary if you aren't boiling the full volume of wort. The increased gravity of a partial boil will; increase the malliard reaction in the wort (what causes the color to darken, same thing that makes toast brown), and reduce the amount of isomerization of alpha acids in the hops resulting in lower than expected IBUs (less bitter/more sweet).

+1 to what barely water said...to be honest i got lost in his post when he said "malliard" and "isomerization"

Also, rehydrating the yeast allows their cell walls to become pliable again. If you just throw the dried yeast into wort, the cell wall cannot regulate what comes in or out of the cell properly and many cells die.

Dumping the yeast into wort kills about half the cells and weakens the rest. Due to the high cell count, there will always be enough left to ferment the batch.

I'm trying to understand the yeast answer.

So if I rehydrate, it saves more yeast cells.

If I don't rehydrate I may lose 50% of the yeast cells, but it's no big deal because most manufacturers give me enough yeast to compensate for a 50% mortality of cells

Am I close here?

As far as leaving the malt late into the boil... how much? how late? I've been told 1/2 at the start, 1/2 at the 10minutes to go mark. I always do a partial boil on the wort.. don't have the equipment to boil the full 5gal.

j_jones84 said:

I'm trying to understand the yeast answer.

So if I rehydrate, it saves more yeast cells.

If I don't rehydrate I may lose 50% of the yeast cells, but it's no big deal because most manufacturers give me enough yeast to compensate for a 50% mortality of cells

Am I close here?

As far as leaving the malt late into the boil... how much? how late? I've been told 1/2 at the start, 1/2 at the 10minutes to go mark. I always do a partial boil on the wort.. don't have the equipment to boil the full 5gal.

Click to expand...

A partial boil of wort is fine, as long as your just making 5 gallons. I have never boiled a full 5 gallons of wort for 5 gallons of brew, it isnt necessary. Unless you are trying to make a VERY specific recipe it isnt necessary to stagger the addition of malts. In regards to rehydrating yeast, it is not 100% necesary and I have made plenty of batches without rehydrating, but it is a good habit to get into. It will help the yeast take over fermentation faster eliminating any other bacteria, and reducing esters. One side affect of a large lag time wil spoil beer and another will give a batch off flavors. Just better safe than sorry. If you are brewing a high gravity beer, it is especially important to rehydrate the yeast and make a yeast starter in order to get a complete fermentation. Hope this helps, just my 2 cents.

Cool. Rehydrating the yeast didn't seem to be much of a pain at all. Something simple I did while other stuff was in the works.

Making a starter seems like more of a pain, but I guess I'll cross that bridge if I make some HGravity beers.. which I'm not so sure I ever will.

As far as late malt additions, I was told it would "give the beer less of the caramel flavors that are associated with extract brewing"

I always, in every extract batch I did, added about half at the beginning and half at the end. It really comes in handy when doing partial boils. Sit back, I'm about to throw out some numbers that will make you want a new kettle fast...

The maximum threshold of IBUs in a given batch of beer is 100, anything over that is only adding to flavor (and head retention and mouthfeel). This maximum number is also only in worts of around 1.050. Now if you are boiling 3 gal down to about 2.5, and adding 2.5 gal of wort, then your maximum is already sliced down to 50 IBUs in a batch, and that is still with a wort gravity of 1.050 or below.

Now, with a full boil if you are trying to reach a final gravity 1.050, then you will have near 100% efficiency when it come to alpha acid isomerization and IBU absorption, and you can reach the 100 IBU mark, since you would be starting the boil around 1.044. When using LME, this will be about 7 lbs. If you put 7 lbs of LME into only 3 gallons of wort, then you are starting with a pre boil gravity of 1.084, boiling down to probably around 2.5gal at 1.100 before topping of with water to reach your OG of 1.050. Far above the ideal IBU efficiency gravity. This will leave you with a wort that has a max IBU rating of approx. 82.7, not too bad, but wait. After topping off, you will have only 41.4 IBUs.

So without doing a late extract addition you maximum IBU level would be 41.4, not quite the hop bomb you may have thought you were making.

Now, if you add say, half at the end, lets see what that does. You pre boil gravity will be around 1.042 (very close to that of a full wort boil), and you will boil off around to about 2.5 gal at 1.050, perfect. So now you have 100 IBUs, top off and you are at you maximum of 50 IBUs, still not the hop bomb you thought, but better. If you are only adding 2 gal of top off water, then you max IBU will be 60, 1.5 gal and the max IBU is 70, 1 gal is 80, .5 gal is 90 and not topping off can get you the maximum IBU level of 100.

That's why you should do a late extract addition.

Not to mention the caramelization, "extract twang" thing.

I should also mention that most of the brewing software out there soes not stop at 100 IBU, but does take into account the lesser effeciancy due to higher gravity boils. BeerSmith and the other software will tell you it has 200 IBU's when it really only has around 90, so a little rough math is required to figure it out sometimes, but for these purposes, you can see the point.