TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The B100 biodiesel contains 0.10-0.01 (preferably 0.15-0.01, especially 0.20-0.01) or 0.03 wt.% total glycerin. The B100 biodiesel contains less than about 0.40 (preferably less than 0.20) wt.% monoglyceride; less than 0.04 (preferably less than 0.02) wt.% monopalmitin; and less than about 0.015 (preferably less than 0.01) wt.% monostearin. The B100 biodiesel contains monopalmitin (less than about 0.04 wt.%) and monostearin (less than about 0.015 wt.%). The mixture is in a ratio of 50% to 2% biodiesel to diesel. The mixture is a B50, B20, B5, B2.5 or B2 biodiesel blend. The base diesel fuel meets the specifications for ASTM Grade No. 2 D diesel fuel. The base diesel fuel has a cloud point of less than or equal to -14 (preferably less than or equal to -7) degrees F. The blend is a B20 blend, B5 blend, B2.5 blend or B2 blend. The B100 biodiesel has filtration time of less than 100 (preferably less than 50, especially less than 20) seconds or has filtration time that is equal to the filtration time of the B0 diesel fuel. Preferred Composition: The composition further comprises a cold flow improver effective to lower the LTFT temperature lower than the cloud point of the base fuel. EXAMPLE - A series of B2.5 blends made from different B100 sources were tested with the Low-Temperature Flow Test (LTFT) procedure. This test was designed to determine if the B100 source actually had an effect on the low temperature filter characteristics of a B2.5 blend. The filtration time of the B100 source in the modified 'Draft' National Biodiesel Board (NBB) filter time procedure was indicated across the top of the graph, with B100 filtration times of around 10 seconds up to 340 seconds for the B100 with the highest contamination level. The results indicated that the B100 source had a significant effect on the filter characteristics of the B2.5 blend, especially when the B100 exhibited a filter time of less than 200 seconds in the modified 'Draft' NBB filter time protocol. This surprising result showed again that the composition was superior to the current fuels that met all industry standards.